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    <title>DEV Community: kensaadi</title>
    <description>The latest articles on DEV Community by kensaadi (@kensaadi).</description>
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    <item>
      <title>I gave Tailwind typed props. Then it ate React Hook Form.</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Fri, 19 Jun 2026 17:31:59 +0000</pubDate>
      <link>https://dev.to/kensaadi/i-gave-tailwind-typed-props-then-it-ate-react-hook-form-1dlj</link>
      <guid>https://dev.to/kensaadi/i-gave-tailwind-typed-props-then-it-ate-react-hook-form-1dlj</guid>
      <description>&lt;p&gt;I spent years thinking my React forms were a CSS problem.&lt;/p&gt;

&lt;p&gt;They weren't. They were a &lt;em&gt;wiring&lt;/em&gt; problem — and I'd been paying for it on every single field, in every single project.&lt;/p&gt;

&lt;p&gt;This is the story of how questioning one small thing — &lt;em&gt;why is styling hidden inside strings?&lt;/em&gt; — led me somewhere I didn't expect: to components that already know what form they live in, who's allowed to use them, and when they should exist at all.&lt;/p&gt;

&lt;h2&gt;
  
  
  It started with className
&lt;/h2&gt;

&lt;p&gt;Like most React developers, I've written this code thousands of times:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt; &lt;span class="na"&gt;className&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"flex items-center justify-between gap-4 p-4 rounded-xl bg-white"&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;There's nothing wrong with Tailwind. It solved a real category of problems that hand-written CSS created — naming, dead styles, cascade surprises. I'm not here to relitigate that. I reach for it on every project.&lt;/p&gt;

&lt;p&gt;But after years of building business apps, one thing kept nagging me.&lt;/p&gt;

&lt;p&gt;React is built around props. Everything is a prop. Except styling — layout, spacing, color, visual state — which lives inside one big opaque string. No autocomplete. No type-checking. No refactor safety. The compiler has no idea what's in there.&lt;/p&gt;

&lt;p&gt;So I asked a dumb question:&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;What would Tailwind components look like if every utility that mattered were a typed prop instead of a substring?&lt;/p&gt;
&lt;/blockquote&gt;

&lt;h2&gt;
  
  
  Props-first, on top of Tailwind
&lt;/h2&gt;

&lt;p&gt;Instead of a className soup, I wanted the visual API to be the type system:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Button&lt;/span&gt; &lt;span class="na"&gt;variant&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"solid"&lt;/span&gt; &lt;span class="na"&gt;color&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"primary"&lt;/span&gt; &lt;span class="na"&gt;size&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"md"&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  Save
&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;Button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;code&gt;variant&lt;/code&gt;, &lt;code&gt;color&lt;/code&gt;, &lt;code&gt;size&lt;/code&gt; — autocompleted, type-checked, self-documenting. Behind the scenes each one still resolves to plain Tailwind utility classes (compiled with &lt;a href="https://www.tailwind-variants.org/" rel="noopener noreferrer"&gt;&lt;code&gt;tailwind-variants&lt;/code&gt;&lt;/a&gt;), and every color and spacing value comes from design tokens wired into the Tailwind config through a preset — not magic numbers, the same scale across the whole system.&lt;/p&gt;

&lt;p&gt;&lt;code&gt;className&lt;/code&gt; isn't even on the component. There's exactly one override path: an &lt;code&gt;sx&lt;/code&gt; escape hatch, where &lt;code&gt;tailwind-merge&lt;/code&gt; guarantees your utility wins over the variant's. One way in, no specificity roulette.&lt;/p&gt;

&lt;p&gt;Under the hood the interactive primitives are &lt;a href="https://www.radix-ui.com/" rel="noopener noreferrer"&gt;Radix&lt;/a&gt; (and React Aria for the hard ones), so accessibility, focus management, and keyboard behavior aren't something I reinvented badly at 11pm.&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;"Wait, this is just Chakra / MUI's &lt;code&gt;sx&lt;/code&gt;."&lt;/p&gt;
&lt;/blockquote&gt;

&lt;p&gt;Fair — props-first styling isn't a new idea, and I'm not going to pretend I invented it. But there's a real difference: this is &lt;strong&gt;build-time Tailwind utilities&lt;/strong&gt; over &lt;strong&gt;headless Radix primitives&lt;/strong&gt;, not a runtime CSS-in-JS engine. Dark mode is a CSS-variable swap from a theme layer — the &lt;em&gt;same&lt;/em&gt; class resolves to a different value when a &lt;code&gt;data-&lt;/code&gt; attribute flips, no &lt;code&gt;dark:&lt;/code&gt; explosion in every recipe.&lt;/p&gt;

&lt;p&gt;And honestly? The styling was never the interesting part. It was just the door.&lt;/p&gt;

&lt;h2&gt;
  
  
  Then React Hook Form happened
&lt;/h2&gt;

&lt;p&gt;The first real app exposed the actual problem.&lt;/p&gt;

&lt;p&gt;A typical RHF field looks like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Controller&lt;/span&gt;
  &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"email"&lt;/span&gt;
  &lt;span class="na"&gt;control&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
  &lt;span class="na"&gt;render&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;fieldState&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;input&lt;/span&gt; &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;...&lt;/span&gt;&lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt; &lt;span class="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;p&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;message&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;p&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Nothing wrong with it. But by your 50th field, the shape is undeniable. Controller, render prop, field wiring, error wiring — copy, paste, again. And again. And again.&lt;/p&gt;

&lt;p&gt;So I asked the next dumb question: &lt;em&gt;why does every developer manually re-connect every field to the form?&lt;/em&gt;&lt;/p&gt;

&lt;p&gt;What if the component already understood forms?&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;TextField&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"email"&lt;/span&gt; &lt;span class="na"&gt;label&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"Email"&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;PasswordField&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"password"&lt;/span&gt; &lt;span class="na"&gt;label&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"Password"&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;No &lt;code&gt;Controller&lt;/code&gt;. No render prop. No error plumbing. The field reads its value, validation state, and error directly from a form bridge via context — and it errors only after blur or submit, so you don't get red text screaming at someone mid-keystroke.&lt;/p&gt;

&lt;p&gt;This is where I stopped thinking I'd rebuilt Tailwind. The real cost in business UIs was never CSS or even rendering. It was &lt;strong&gt;orchestration&lt;/strong&gt; — the glue wiring everything to everything else.&lt;/p&gt;

&lt;h2&gt;
  
  
  Fields that know when they exist
&lt;/h2&gt;

&lt;p&gt;Every app eventually grows dependent fields:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;customerType&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;watch&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;customerType&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;customerType&lt;/span&gt; &lt;span class="o"&gt;!==&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;business&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="nf"&gt;setValue&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;vatNumber&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;""&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;customerType&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;A &lt;code&gt;watch&lt;/code&gt;, a conditional render, a cleanup effect — per rule, times hundreds of rules. That's not business logic. It's plumbing.&lt;/p&gt;

&lt;p&gt;What if the field described its own condition?&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;TextField&lt;/span&gt;
  &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"vatNumber"&lt;/span&gt;
  &lt;span class="na"&gt;visibleWhen&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;field&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;customerType&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;equals&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;business&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;No &lt;code&gt;watch&lt;/code&gt;. No effect. No manual reset. The field already knows when it should be on screen — and the engine handles the teardown.&lt;/p&gt;

&lt;h2&gt;
  
  
  Buttons that know who's allowed to press them
&lt;/h2&gt;

&lt;p&gt;Same story with permissions, scattered across every screen:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;includes&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;invoice:update&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Save&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Why is that check &lt;em&gt;outside&lt;/em&gt; the component? Why doesn't the button know who can use it?&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Button&lt;/span&gt; &lt;span class="na"&gt;access&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"invoice:update"&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Save&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;Button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The rule lives where it matters — on the node itself. Unauthorized can mean hide, disable, or readonly, your call. The permission logic stops being a render-time &lt;code&gt;&amp;amp;&amp;amp;&lt;/code&gt; smeared across the codebase.&lt;/p&gt;

&lt;h2&gt;
  
  
  The part I didn't plan
&lt;/h2&gt;

&lt;p&gt;Here's the reveal, and it's the bit I'm actually proud of.&lt;/p&gt;

&lt;p&gt;There are &lt;strong&gt;two&lt;/strong&gt; component libraries: one rendered with MUI, one rendered with Tailwind + Radix. Same component names, same orchestration props — &lt;code&gt;name&lt;/code&gt;, &lt;code&gt;visibleWhen&lt;/code&gt;, &lt;code&gt;access&lt;/code&gt; — different pixels.&lt;/p&gt;

&lt;p&gt;They share &lt;strong&gt;zero styling code&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;What they &lt;em&gt;do&lt;/em&gt; share is one headless engine: the form bridge, the visibility engine, the RBAC layer. The application-awareness — &lt;em&gt;what a field knows about the app it lives in&lt;/em&gt; — is a separate, framework-agnostic core. The styling layer is swappable. The intelligence underneath is not.&lt;/p&gt;

&lt;p&gt;That's when it clicked. I wasn't building UI components anymore. I was building &lt;strong&gt;application-aware&lt;/strong&gt; components — things that understand styling, forms, validation, visibility, and permissions, not because they contain business logic, but because they understand how they &lt;em&gt;participate&lt;/em&gt; in an application.&lt;/p&gt;

&lt;h2&gt;
  
  
  Where this lives
&lt;/h2&gt;

&lt;p&gt;This is &lt;a href="https://github.com/kensaadi/dashforge" rel="noopener noreferrer"&gt;DashForge&lt;/a&gt; — React + MUI + React Hook Form + Tailwind CSS, with the Tailwind track (&lt;code&gt;@dashforge/tw&lt;/code&gt;) built on Radix and &lt;code&gt;tailwind-variants&lt;/code&gt;. It's an early alpha; the core architecture is already running in real apps, the API surface is still settling.&lt;/p&gt;

&lt;p&gt;If the orchestration idea resonates — if you've also written the same &lt;code&gt;watch&lt;/code&gt; / &lt;code&gt;useEffect&lt;/code&gt; / permission check for the hundredth time — the repo is here:&lt;/p&gt;

&lt;p&gt;👉 &lt;strong&gt;&lt;a href="https://github.com/kensaadi/dashforge" rel="noopener noreferrer"&gt;https://github.com/kensaadi/dashforge&lt;/a&gt;&lt;/strong&gt;&lt;br&gt;
👉 &lt;strong&gt;&lt;a href="https://dashforge-ui.com/tw" rel="noopener noreferrer"&gt;https://dashforge-ui.com/tw&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;A star helps me gauge whether to keep pushing this. And I'd genuinely like to hear how &lt;em&gt;you&lt;/em&gt; deal with form orchestration at scale — drop it in the comments.&lt;/p&gt;

</description>
      <category>react</category>
      <category>tailwindcss</category>
      <category>typescript</category>
      <category>frontend</category>
    </item>
    <item>
      <title>Production RBAC patterns for Go and Node startups</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Wed, 17 Jun 2026 09:56:56 +0000</pubDate>
      <link>https://dev.to/kensaadi/production-rbac-patterns-for-go-and-node-startups-1ddl</link>
      <guid>https://dev.to/kensaadi/production-rbac-patterns-for-go-and-node-startups-1ddl</guid>
      <description>&lt;p&gt;A founder told me last year:&lt;/p&gt;

&lt;blockquote&gt;
&lt;p&gt;"We need admin features shipped by Friday. Can we just hardcode the roles for now?"&lt;/p&gt;
&lt;/blockquote&gt;

&lt;p&gt;That was 7 months ago. They're still paying for that decision today.&lt;/p&gt;

&lt;p&gt;This article is the breakdown I wish I had given them before that Friday — the patterns that separate a quick MVP version of RBAC from one that won't bite you back in six months.&lt;/p&gt;

&lt;p&gt;If you're a startup CTO, technical founder, or senior engineer about to ship admin/dashboard features for the first time, this is for you.&lt;/p&gt;

&lt;h2&gt;
  
  
  The 4 signs your RBAC is a time bomb
&lt;/h2&gt;

&lt;p&gt;I've reviewed this exact pattern in 5+ early-stage codebases. Every one of them eventually hit the wall. Look for these signs:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;1. Roles hardcoded in the JWT&lt;/strong&gt;&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight json"&gt;&lt;code&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="nl"&gt;"sub"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"user_123"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="nl"&gt;"role"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"admin"&lt;/span&gt;&lt;span class="w"&gt;
&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="w"&gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Simple. Until you need to:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Add a new role → migration + token refresh strategy&lt;/li&gt;
&lt;li&gt;Give one user a temporary elevated permission → "we'll just reissue tokens"&lt;/li&gt;
&lt;li&gt;Audit who had &lt;code&gt;admin&lt;/code&gt; last month → good luck&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;2. Permission checks scattered across 40+ controllers&lt;/strong&gt;&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight go"&gt;&lt;code&gt;&lt;span class="c"&gt;// In every single handler:&lt;/span&gt;
&lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="n"&gt;user&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Role&lt;/span&gt; &lt;span class="o"&gt;!=&lt;/span&gt; &lt;span class="s"&gt;"admin"&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Status&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;403&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;JSON&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="o"&gt;...&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;By the time you have 30 endpoints, you've made the same mistake 30 times. Refactoring is a full sprint.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;3. One &lt;code&gt;admin&lt;/code&gt; superuser that can do everything&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Until a sales rep accidentally deletes a customer record because they were elevated to admin "just for that one task last week."&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;4. Zero audit trail&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;When the data goes missing, your only investigative tool is &lt;code&gt;git blame&lt;/code&gt; on the source code and a desperate grep through CloudWatch logs.&lt;/p&gt;

&lt;p&gt;If you've nodded at any of these — keep reading.&lt;/p&gt;

&lt;h2&gt;
  
  
  The real problem: policies-as-code
&lt;/h2&gt;

&lt;p&gt;Most teams treat permissions like business logic. They live in source files, gated by &lt;code&gt;if&lt;/code&gt; statements, deployed with the rest of the code.&lt;/p&gt;

&lt;p&gt;This is the original sin.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Code changes need deploys. Permissions change daily.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;When marketing onboards a new role next quarter, when a customer success rep needs view-only access to billing, when legal asks "who could have read this customer's data on Tuesday at 3pm?" — every one of these requires a permission change. If permissions live in code, every one of these requires a deploy.&lt;/p&gt;

&lt;p&gt;Production RBAC starts with one shift in mental model: &lt;strong&gt;permissions are data, not code&lt;/strong&gt;.&lt;/p&gt;

&lt;h2&gt;
  
  
  Three rules for production-grade RBAC
&lt;/h2&gt;

&lt;h3&gt;
  
  
  Rule 1: Policy-as-data, not policy-as-code
&lt;/h3&gt;

&lt;p&gt;Policies live in your database. Source code only knows how to &lt;em&gt;check&lt;/em&gt; them, not &lt;em&gt;define&lt;/em&gt; them.&lt;/p&gt;

&lt;p&gt;A reasonable schema (Postgres flavor, equivalent in MongoDB):&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight sql"&gt;&lt;code&gt;&lt;span class="c1"&gt;-- Roles&lt;/span&gt;
&lt;span class="k"&gt;CREATE&lt;/span&gt; &lt;span class="k"&gt;TABLE&lt;/span&gt; &lt;span class="n"&gt;roles&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="n"&gt;id&lt;/span&gt;         &lt;span class="nb"&gt;SERIAL&lt;/span&gt; &lt;span class="k"&gt;PRIMARY&lt;/span&gt; &lt;span class="k"&gt;KEY&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;name&lt;/span&gt;       &lt;span class="nb"&gt;TEXT&lt;/span&gt; &lt;span class="k"&gt;UNIQUE&lt;/span&gt; &lt;span class="k"&gt;NOT&lt;/span&gt; &lt;span class="k"&gt;NULL&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;created_at&lt;/span&gt; &lt;span class="n"&gt;TIMESTAMPTZ&lt;/span&gt; &lt;span class="k"&gt;DEFAULT&lt;/span&gt; &lt;span class="n"&gt;now&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="c1"&gt;-- Permissions (action on resource)&lt;/span&gt;
&lt;span class="k"&gt;CREATE&lt;/span&gt; &lt;span class="k"&gt;TABLE&lt;/span&gt; &lt;span class="n"&gt;permissions&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="n"&gt;id&lt;/span&gt;         &lt;span class="nb"&gt;SERIAL&lt;/span&gt; &lt;span class="k"&gt;PRIMARY&lt;/span&gt; &lt;span class="k"&gt;KEY&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;resource&lt;/span&gt;   &lt;span class="nb"&gt;TEXT&lt;/span&gt; &lt;span class="k"&gt;NOT&lt;/span&gt; &lt;span class="k"&gt;NULL&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;   &lt;span class="c1"&gt;-- e.g., "orders", "customers"&lt;/span&gt;
  &lt;span class="n"&gt;action&lt;/span&gt;     &lt;span class="nb"&gt;TEXT&lt;/span&gt; &lt;span class="k"&gt;NOT&lt;/span&gt; &lt;span class="k"&gt;NULL&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;   &lt;span class="c1"&gt;-- e.g., "read", "delete"&lt;/span&gt;
  &lt;span class="k"&gt;UNIQUE&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;action&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="c1"&gt;-- Role &amp;lt;-&amp;gt; Permission mapping&lt;/span&gt;
&lt;span class="k"&gt;CREATE&lt;/span&gt; &lt;span class="k"&gt;TABLE&lt;/span&gt; &lt;span class="n"&gt;role_permissions&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="n"&gt;role_id&lt;/span&gt;        &lt;span class="nb"&gt;INTEGER&lt;/span&gt; &lt;span class="k"&gt;REFERENCES&lt;/span&gt; &lt;span class="n"&gt;roles&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;id&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="n"&gt;permission_id&lt;/span&gt;  &lt;span class="nb"&gt;INTEGER&lt;/span&gt; &lt;span class="k"&gt;REFERENCES&lt;/span&gt; &lt;span class="n"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;id&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="k"&gt;PRIMARY&lt;/span&gt; &lt;span class="k"&gt;KEY&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;role_id&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;permission_id&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="c1"&gt;-- User &amp;lt;-&amp;gt; Role mapping&lt;/span&gt;
&lt;span class="k"&gt;CREATE&lt;/span&gt; &lt;span class="k"&gt;TABLE&lt;/span&gt; &lt;span class="n"&gt;user_roles&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="n"&gt;user_id&lt;/span&gt;  &lt;span class="nb"&gt;INTEGER&lt;/span&gt; &lt;span class="k"&gt;REFERENCES&lt;/span&gt; &lt;span class="n"&gt;users&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;id&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="n"&gt;role_id&lt;/span&gt;  &lt;span class="nb"&gt;INTEGER&lt;/span&gt; &lt;span class="k"&gt;REFERENCES&lt;/span&gt; &lt;span class="n"&gt;roles&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;id&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="k"&gt;PRIMARY&lt;/span&gt; &lt;span class="k"&gt;KEY&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;user_id&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;role_id&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;In MongoDB the same idea is one document per role:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight json"&gt;&lt;code&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="nl"&gt;"_id"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"sales"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="nl"&gt;"permissions"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="w"&gt;
    &lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="nl"&gt;"resource"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"customers"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="nl"&gt;"action"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"read"&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="p"&gt;},&lt;/span&gt;&lt;span class="w"&gt;
    &lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="nl"&gt;"resource"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"orders"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;&lt;span class="w"&gt;    &lt;/span&gt;&lt;span class="nl"&gt;"action"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"read"&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="p"&gt;},&lt;/span&gt;&lt;span class="w"&gt;
    &lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="nl"&gt;"resource"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"orders"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;&lt;span class="w"&gt;    &lt;/span&gt;&lt;span class="nl"&gt;"action"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"create"&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;&lt;span class="w"&gt;
  &lt;/span&gt;&lt;span class="nl"&gt;"updatedAt"&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;&lt;span class="w"&gt; &lt;/span&gt;&lt;span class="s2"&gt;"2026-06-10T14:00:00Z"&lt;/span&gt;&lt;span class="w"&gt;
&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="w"&gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The difference: now you change a permission with &lt;code&gt;UPDATE&lt;/code&gt;, not with &lt;code&gt;git push&lt;/code&gt;.&lt;/p&gt;

&lt;h3&gt;
  
  
  Rule 2: Granular permissions (action-level, not role-level)
&lt;/h3&gt;

&lt;p&gt;The wrong abstraction is &lt;code&gt;role === permission&lt;/code&gt;. The right abstraction is &lt;code&gt;permission === (resource, action)&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;Bad:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight go"&gt;&lt;code&gt;&lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="n"&gt;user&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Role&lt;/span&gt; &lt;span class="o"&gt;==&lt;/span&gt; &lt;span class="s"&gt;"admin"&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="c"&gt;/* do everything */&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Good:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight go"&gt;&lt;code&gt;&lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="n"&gt;user&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="s"&gt;"orders"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="s"&gt;"delete"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="c"&gt;/* delete the order */&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The &lt;code&gt;Can()&lt;/code&gt; function looks up: does this user, through any of their roles, have the permission &lt;code&gt;(orders, delete)&lt;/code&gt;? Cache it per-request with the user's permission set loaded once on auth.&lt;/p&gt;

&lt;p&gt;This means:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;New permission? Insert one row. No deploy.&lt;/li&gt;
&lt;li&gt;Promote a role? Add a row to &lt;code&gt;role_permissions&lt;/code&gt;. No deploy.&lt;/li&gt;
&lt;li&gt;Demote a user? Remove a row from &lt;code&gt;user_roles&lt;/code&gt;. No deploy.&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Rule 3: Audit trail — non-negotiable
&lt;/h3&gt;

&lt;p&gt;Every sensitive action logs to an append-only table:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight sql"&gt;&lt;code&gt;&lt;span class="k"&gt;CREATE&lt;/span&gt; &lt;span class="k"&gt;TABLE&lt;/span&gt; &lt;span class="n"&gt;audit_log&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="n"&gt;id&lt;/span&gt;         &lt;span class="n"&gt;BIGSERIAL&lt;/span&gt; &lt;span class="k"&gt;PRIMARY&lt;/span&gt; &lt;span class="k"&gt;KEY&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;actor_id&lt;/span&gt;   &lt;span class="nb"&gt;INTEGER&lt;/span&gt; &lt;span class="k"&gt;REFERENCES&lt;/span&gt; &lt;span class="n"&gt;users&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;id&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="n"&gt;action&lt;/span&gt;     &lt;span class="nb"&gt;TEXT&lt;/span&gt; &lt;span class="k"&gt;NOT&lt;/span&gt; &lt;span class="k"&gt;NULL&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;              &lt;span class="c1"&gt;-- e.g., "order.delete"&lt;/span&gt;
  &lt;span class="n"&gt;resource&lt;/span&gt;   &lt;span class="nb"&gt;TEXT&lt;/span&gt; &lt;span class="k"&gt;NOT&lt;/span&gt; &lt;span class="k"&gt;NULL&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;              &lt;span class="c1"&gt;-- e.g., "orders/42"&lt;/span&gt;
  &lt;span class="k"&gt;before&lt;/span&gt;     &lt;span class="n"&gt;JSONB&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;                      &lt;span class="c1"&gt;-- snapshot before&lt;/span&gt;
  &lt;span class="k"&gt;after&lt;/span&gt;      &lt;span class="n"&gt;JSONB&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;                      &lt;span class="c1"&gt;-- snapshot after (NULL for delete)&lt;/span&gt;
  &lt;span class="n"&gt;ip_address&lt;/span&gt; &lt;span class="n"&gt;INET&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;user_agent&lt;/span&gt; &lt;span class="nb"&gt;TEXT&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="n"&gt;created_at&lt;/span&gt; &lt;span class="n"&gt;TIMESTAMPTZ&lt;/span&gt; &lt;span class="k"&gt;DEFAULT&lt;/span&gt; &lt;span class="n"&gt;now&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Append-only. No &lt;code&gt;UPDATE&lt;/code&gt;, no &lt;code&gt;DELETE&lt;/code&gt;. When the customer record disappears, you have a complete trail of who, when, and what changed.&lt;/p&gt;

&lt;p&gt;This sounds like overhead until the first time you need it. Then it's the cheapest insurance you ever bought.&lt;/p&gt;

&lt;h2&gt;
  
  
  RBAC vs ABAC vs ReBAC: which one do you need?
&lt;/h2&gt;

&lt;p&gt;A quick decision tree:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Plain RBAC&lt;/strong&gt; — most startups need this and nothing more.&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Users have roles. Roles have permissions. Done.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;ABAC&lt;/strong&gt; (Attribute-Based Access Control) — only if your access depends on attributes of the request, not just the user.&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;"Sales reps can only see customers in their region"&lt;/li&gt;
&lt;li&gt;"This document is editable only during business hours"&lt;/li&gt;
&lt;li&gt;ABAC adds policy engines and complexity. Skip unless required.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;ReBAC&lt;/strong&gt; (Relationship-Based, Zanzibar-style) — only for sharing/multi-tenant graphs.&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;"User A shared this document with User B who shared a folder with Team C"&lt;/li&gt;
&lt;li&gt;Google Docs, Notion, Figma need this. Your B2B SaaS probably doesn't.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;If you're not sure — start with RBAC + audit log. You can always layer ABAC on top later.&lt;/p&gt;

&lt;h2&gt;
  
  
  A concrete implementation walkthrough
&lt;/h2&gt;

&lt;p&gt;Here's the minimal viable production-grade RBAC in real code.&lt;/p&gt;

&lt;h3&gt;
  
  
  Go middleware (Fiber)
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight go"&gt;&lt;code&gt;&lt;span class="k"&gt;package&lt;/span&gt; &lt;span class="n"&gt;middleware&lt;/span&gt;

&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="s"&gt;"github.com/gofiber/fiber/v2"&lt;/span&gt;
&lt;span class="p"&gt;)&lt;/span&gt;

&lt;span class="k"&gt;type&lt;/span&gt; &lt;span class="n"&gt;PermissionChecker&lt;/span&gt; &lt;span class="k"&gt;interface&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="n"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;userID&lt;/span&gt; &lt;span class="kt"&gt;int&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;action&lt;/span&gt; &lt;span class="kt"&gt;string&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kt"&gt;bool&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="kt"&gt;error&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="k"&gt;func&lt;/span&gt; &lt;span class="n"&gt;RequirePermission&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;checker&lt;/span&gt; &lt;span class="n"&gt;PermissionChecker&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;action&lt;/span&gt; &lt;span class="kt"&gt;string&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="n"&gt;fiber&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Handler&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="k"&gt;func&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;c&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt;&lt;span class="n"&gt;fiber&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Ctx&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="kt"&gt;error&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="n"&gt;userID&lt;/span&gt; &lt;span class="o"&gt;:=&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Locals&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="s"&gt;"user_id"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kt"&gt;int&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;

        &lt;span class="n"&gt;allowed&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;err&lt;/span&gt; &lt;span class="o"&gt;:=&lt;/span&gt; &lt;span class="n"&gt;checker&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;userID&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;action&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
        &lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="n"&gt;err&lt;/span&gt; &lt;span class="o"&gt;!=&lt;/span&gt; &lt;span class="no"&gt;nil&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Status&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;500&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;JSON&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;fiber&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Map&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="s"&gt;"error"&lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt; &lt;span class="s"&gt;"permission check failed"&lt;/span&gt;&lt;span class="p"&gt;})&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;
        &lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="o"&gt;!&lt;/span&gt;&lt;span class="n"&gt;allowed&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Status&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;403&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;JSON&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;fiber&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Map&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="s"&gt;"error"&lt;/span&gt;&lt;span class="o"&gt;:&lt;/span&gt; &lt;span class="s"&gt;"forbidden"&lt;/span&gt;&lt;span class="p"&gt;})&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;
        &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Next&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="c"&gt;// Usage in routes:&lt;/span&gt;
&lt;span class="c"&gt;// app.Delete("/orders/:id",&lt;/span&gt;
&lt;span class="c"&gt;//     RequirePermission(permChecker, "orders", "delete"),&lt;/span&gt;
&lt;span class="c"&gt;//     handlers.DeleteOrder)&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The middleware is &lt;strong&gt;stateless&lt;/strong&gt; about which roles exist. It just asks: "can this user do this action on this resource?" The answer comes from the DB.&lt;/p&gt;

&lt;h3&gt;
  
  
  Node middleware (Express)
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="c1"&gt;// middleware/requirePermission.js&lt;/span&gt;
&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;requirePermission&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;checker&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;req&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;res&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;next&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;try&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;allowed&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;checker&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;can&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;req&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;user&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;id&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
      &lt;span class="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="o"&gt;!&lt;/span&gt;&lt;span class="nx"&gt;allowed&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;res&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;status&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;403&lt;/span&gt;&lt;span class="p"&gt;).&lt;/span&gt;&lt;span class="nf"&gt;json&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;forbidden&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;});&lt;/span&gt;
      &lt;span class="p"&gt;}&lt;/span&gt;
      &lt;span class="nf"&gt;next&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;catch &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;err&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;res&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;status&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;500&lt;/span&gt;&lt;span class="p"&gt;).&lt;/span&gt;&lt;span class="nf"&gt;json&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;permission check failed&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;});&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;
  &lt;span class="p"&gt;};&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="nx"&gt;module&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;exports&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;requirePermission&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="c1"&gt;// Usage:&lt;/span&gt;
&lt;span class="c1"&gt;// router.delete('/orders/:id',&lt;/span&gt;
&lt;span class="c1"&gt;//   requirePermission(permChecker, 'orders', 'delete'),&lt;/span&gt;
&lt;span class="c1"&gt;//   handlers.deleteOrder);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Same pattern, different language. The permission set is loaded once at login and cached on the user session — &lt;code&gt;checker.can()&lt;/code&gt; is an in-memory lookup against a &lt;code&gt;Set&lt;/code&gt; per request.&lt;/p&gt;

&lt;h3&gt;
  
  
  Frontend gating: where most teams stop too early
&lt;/h3&gt;

&lt;p&gt;Most articles end here with a one-component &lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt; example and a "server-side check is the source of truth" disclaimer. That's correct, but it's the &lt;strong&gt;bare minimum&lt;/strong&gt; of what production RBAC needs on the frontend.&lt;/p&gt;

&lt;p&gt;A real RBAC layer on the frontend has at least 5 concerns:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;
&lt;strong&gt;Hook-level access&lt;/strong&gt; — read user permissions anywhere without prop drilling&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Inline gating&lt;/strong&gt; — show/hide buttons, columns, table actions&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Route-level gating&lt;/strong&gt; — block entire pages, redirect unauthorized users&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Admin UI&lt;/strong&gt; — non-engineers need to view/edit roles and permissions&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Audit visibility&lt;/strong&gt; — someone needs to read the audit log without DB access&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Skip any of these and you'll re-invent them six months later. Here's the shape they should have.&lt;/p&gt;

&lt;h4&gt;
  
  
  1. The hook
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight jsx"&gt;&lt;code&gt;&lt;span class="c1"&gt;// useAuth() returns user + a Set of permission keys&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;user&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;permissions&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useAuth&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

&lt;span class="c1"&gt;// usePermissions() is a focused alias when you don't need user data&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;permissions&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;usePermissions&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

&lt;span class="nx"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;has&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;orders:delete&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;  &lt;span class="c1"&gt;// true | false&lt;/span&gt;
&lt;span class="nx"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;canAny&lt;/span&gt;&lt;span class="p"&gt;([&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;orders:delete&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;orders:archive&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;span class="nx"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;canAll&lt;/span&gt;&lt;span class="p"&gt;([&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;customers:read&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;customers:update&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The permission set is loaded once on auth, cached in React context, and every check is O(1).&lt;/p&gt;

&lt;h4&gt;
  
  
  2. Inline gating with &lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt;
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight jsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt; &lt;span class="na"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"orders"&lt;/span&gt; &lt;span class="na"&gt;action&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"delete"&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;DeleteButton&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;handleDelete&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;

&lt;span class="c1"&gt;// With a fallback (shows a disabled button + tooltip instead of hiding)&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt;
  &lt;span class="na"&gt;resource&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"orders"&lt;/span&gt;
  &lt;span class="na"&gt;action&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"delete"&lt;/span&gt;
  &lt;span class="na"&gt;fallback&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;DisabledButton&lt;/span&gt; &lt;span class="na"&gt;tooltip&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"You don't have permission to delete orders"&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;DeleteButton&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;handleDelete&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;

&lt;span class="c1"&gt;// With multiple permissions (any of these is enough)&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt; &lt;span class="na"&gt;anyOf&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;orders:delete&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;orders:archive&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;DangerActions&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;Can&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The &lt;code&gt;fallback&lt;/code&gt; prop is the key detail most implementations miss. Hiding a button creates a worse UX than showing it disabled with a "why you can't" tooltip — users feel less broken when they know the rule exists.&lt;/p&gt;

&lt;h4&gt;
  
  
  3. Route-level gating with &lt;code&gt;&amp;lt;RoleGuard&amp;gt;&lt;/code&gt;
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight jsx"&gt;&lt;code&gt;&lt;span class="c1"&gt;// Inside the router&lt;/span&gt;
&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Route&lt;/span&gt;
  &lt;span class="na"&gt;path&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"/admin/orders"&lt;/span&gt;
  &lt;span class="na"&gt;element&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;RoleGuard&lt;/span&gt;
      &lt;span class="na"&gt;anyOf&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;orders:read&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
      &lt;span class="na"&gt;fallback&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;ForbiddenPage&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
      &lt;span class="na"&gt;redirect&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"/dashboard"&lt;/span&gt;
    &lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;OrderManagementPage&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nc"&gt;RoleGuard&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="si"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Whole pages refuse to render. Better than letting the user load the page and then erroring on every API call.&lt;/p&gt;

&lt;h4&gt;
  
  
  4. The admin UI — the part nobody writes themselves
&lt;/h4&gt;

&lt;p&gt;This is where DIY RBAC implementations fall apart. Engineers build the middleware and the hook and stop. Then someone in product asks: &lt;em&gt;"Can sales also export customers?"&lt;/em&gt; and the answer is: &lt;em&gt;"Sure, I'll deploy that change next week."&lt;/em&gt;&lt;/p&gt;

&lt;p&gt;A real admin UI lets non-engineers:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;See the role × permission matrix (the same diagram everyone draws on a whiteboard)&lt;/li&gt;
&lt;li&gt;Toggle permissions per role with a click&lt;/li&gt;
&lt;li&gt;Assign users to roles&lt;/li&gt;
&lt;li&gt;See the audit log filterable by actor, action, date range, IP&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;This is what an &lt;code&gt;&amp;lt;PermissionMatrix&amp;gt;&lt;/code&gt; admin component looks like from the consumer side:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight jsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;PermissionMatrix&lt;/span&gt;
  &lt;span class="na"&gt;roles&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;roles&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;                  &lt;span class="c1"&gt;// ["customer", "sales", "admin"]&lt;/span&gt;
  &lt;span class="na"&gt;resources&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;resources&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;          &lt;span class="c1"&gt;// ["orders", "customers", "products"]&lt;/span&gt;
  &lt;span class="na"&gt;actions&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;read&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;create&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;update&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;delete&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
  &lt;span class="na"&gt;value&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;currentPolicy&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;          &lt;span class="c1"&gt;// current role × permission map&lt;/span&gt;
  &lt;span class="na"&gt;onChange&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;handlePolicyChange&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;  &lt;span class="c1"&gt;// saves to DB, no deploy&lt;/span&gt;
  &lt;span class="na"&gt;readonly&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="o"&gt;!&lt;/span&gt;&lt;span class="nx"&gt;permissions&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;has&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;admin:manage_roles&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Behind it: the same &lt;code&gt;roles&lt;/code&gt; / &lt;code&gt;permissions&lt;/code&gt; / &lt;code&gt;role_permissions&lt;/code&gt; tables from Rule #1. Edits hit the DB directly. No code change, no deploy, no engineer in the loop.&lt;/p&gt;

&lt;h4&gt;
  
  
  5. The audit log viewer
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight jsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;AuditLogViewer&lt;/span&gt;
  &lt;span class="na"&gt;filters&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;actor&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;userId&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="na"&gt;actionPrefix&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;order.&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;       &lt;span class="c1"&gt;// "order.delete", "order.update", etc.&lt;/span&gt;
    &lt;span class="na"&gt;dateRange&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;last30Days&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
  &lt;span class="na"&gt;columns&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;actor&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;action&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;resource&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;before&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;after&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;ip&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
  &lt;span class="na"&gt;exportable&lt;/span&gt;                     &lt;span class="c1"&gt;// CSV export for compliance reviews&lt;/span&gt;
  &lt;span class="na"&gt;paginate&lt;/span&gt;
&lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;When the data goes missing or the auditor asks who did what, you don't &lt;code&gt;psql&lt;/code&gt; into prod. You filter the UI.&lt;/p&gt;

&lt;h2&gt;
  
  
  Audit logging in two lines
&lt;/h2&gt;

&lt;p&gt;Wrap your mutation handlers with a logger:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight go"&gt;&lt;code&gt;&lt;span class="k"&gt;func&lt;/span&gt; &lt;span class="n"&gt;DeleteOrder&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;c&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt;&lt;span class="n"&gt;fiber&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Ctx&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="kt"&gt;error&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="n"&gt;orderID&lt;/span&gt; &lt;span class="o"&gt;:=&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Params&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="s"&gt;"id"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
    &lt;span class="n"&gt;order&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;_&lt;/span&gt; &lt;span class="o"&gt;:=&lt;/span&gt; &lt;span class="n"&gt;db&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;GetOrder&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;orderID&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;

    &lt;span class="k"&gt;if&lt;/span&gt; &lt;span class="n"&gt;err&lt;/span&gt; &lt;span class="o"&gt;:=&lt;/span&gt; &lt;span class="n"&gt;db&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;DeleteOrder&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;orderID&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt; &lt;span class="n"&gt;err&lt;/span&gt; &lt;span class="o"&gt;!=&lt;/span&gt; &lt;span class="no"&gt;nil&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;err&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;

    &lt;span class="n"&gt;audit&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Locals&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="s"&gt;"user_id"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kt"&gt;int&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt; &lt;span class="s"&gt;"order.delete"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="s"&gt;"orders/"&lt;/span&gt;&lt;span class="o"&gt;+&lt;/span&gt;&lt;span class="n"&gt;orderID&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;order&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="no"&gt;nil&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;IP&lt;/span&gt;&lt;span class="p"&gt;(),&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;Get&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="s"&gt;"User-Agent"&lt;/span&gt;&lt;span class="p"&gt;))&lt;/span&gt;

    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="n"&gt;c&lt;/span&gt;&lt;span class="o"&gt;.&lt;/span&gt;&lt;span class="n"&gt;SendStatus&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;204&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Same pattern in Node. The audit log table is append-only. Months from now, when something disappears, you'll have the full trail.&lt;/p&gt;

&lt;h2&gt;
  
  
  The RBAC layer in Dashforge — what end-to-end actually looks like
&lt;/h2&gt;

&lt;p&gt;Everything above — the schema, the middleware, the hooks, the components, the admin UI — is the actual design of the RBAC layer in &lt;a href="https://dashforge-ui.com" rel="noopener noreferrer"&gt;Dashforge&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;The reason this article exists is that &lt;strong&gt;every piece of this puzzle is usually built separately by separate teams&lt;/strong&gt;, in different shapes, with different bugs. The middleware is in one repo, the React &lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt; is invented case-by-case, the audit log is "TODO for next sprint", the admin panel never gets built. Six months later you have four half-finished RBAC systems that don't talk to each other.&lt;/p&gt;

&lt;p&gt;Dashforge ships them as &lt;strong&gt;one coherent layer&lt;/strong&gt;:&lt;/p&gt;

&lt;h3&gt;
  
  
  The full stack, day-1 ready
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;┌──────────────────────────────────────────────────────────────────┐
│  Admin UI (React)                                                 │
│  ── PermissionMatrix   roles × actions toggle grid                │
│  ── UserRolesEditor    assign/revoke roles per user               │
│  ── AuditLogViewer     filter, search, CSV export                 │
└─────────────────┬────────────────────────────────────────────────┘
                  │ same auth context, same permission set
┌─────────────────▼────────────────────────────────────────────────┐
│  React components                                                 │
│  ── useAuth()  /  usePermissions()  /  &amp;lt;Can&amp;gt;  /  &amp;lt;RoleGuard&amp;gt;      │
│  Available in BOTH Tailwind and MUI flavors                       │
└─────────────────┬────────────────────────────────────────────────┘
                  │ HTTP, JWT carries user_id only
┌─────────────────▼────────────────────────────────────────────────┐
│  Backend middleware                                               │
│  ── Go (Fiber) and Node (Express) — same contract                 │
│  ── RequirePermission(resource, action)                           │
│  ── Audit log middleware (auto-wraps mutations)                   │
└─────────────────┬────────────────────────────────────────────────┘
                  │
┌─────────────────▼────────────────────────────────────────────────┐
│  Database (MongoDB, Postgres-ready via provider pattern)          │
│  ── roles, permissions, role_permissions, user_roles, audit_log   │
└──────────────────────────────────────────────────────────────────┘
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Single source of truth — the database. Every layer reads from the same tables. You change a permission once, the change propagates automatically:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Middleware blocks unauthorized requests&lt;/li&gt;
&lt;li&gt;React &lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt; hides UI accordingly&lt;/li&gt;
&lt;li&gt;Audit log records everything&lt;/li&gt;
&lt;li&gt;Admin panel reflects the new state&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;No code changes anywhere. No deploy.&lt;/p&gt;

&lt;h3&gt;
  
  
  What you get on day 1
&lt;/h3&gt;

&lt;p&gt;When you open the checkout-kit, the RBAC layer is &lt;strong&gt;already wired up&lt;/strong&gt; with three working roles and the full admin UI:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Backend (Go or Node — pick one):&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;code&gt;RequirePermission(resource, action)&lt;/code&gt; middleware wrapping every protected route&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;PolicyChecker&lt;/code&gt; service that loads user permissions on auth, caches them per session&lt;/li&gt;
&lt;li&gt;Audit logger that wraps mutation handlers automatically (no per-handler boilerplate)&lt;/li&gt;
&lt;li&gt;REST endpoints for &lt;code&gt;/admin/roles&lt;/code&gt;, &lt;code&gt;/admin/permissions&lt;/code&gt;, &lt;code&gt;/admin/users/:id/roles&lt;/code&gt;, &lt;code&gt;/admin/audit-log&lt;/code&gt;
&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Frontend (Tailwind OR MUI flavor — both shipped):&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;AuthProvider&amp;gt;&lt;/code&gt; initialized in your root component&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;useAuth()&lt;/code&gt; and &lt;code&gt;usePermissions()&lt;/code&gt; hooks ready to import&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt; with &lt;code&gt;fallback&lt;/code&gt;, &lt;code&gt;anyOf&lt;/code&gt;, &lt;code&gt;allOf&lt;/code&gt; props — the full API documented above&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;RoleGuard&amp;gt;&lt;/code&gt; for route-level protection (drop-in for React Router)&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;PermissionMatrix&amp;gt;&lt;/code&gt; admin component — pre-styled, pre-wired to the API&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;UserRolesEditor&amp;gt;&lt;/code&gt; — searchable user list with role assignment&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;&amp;lt;AuditLogViewer&amp;gt;&lt;/code&gt; — filterable, exportable, paginated&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Three roles, pre-seeded:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;code&gt;customer&lt;/code&gt; — read their own orders, update their own profile&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;sales&lt;/code&gt; — read/create/update orders and customers, no delete&lt;/li&gt;
&lt;li&gt;
&lt;code&gt;admin&lt;/code&gt; — everything, plus role/permission management&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Extending to a fourth role is one row in the &lt;code&gt;roles&lt;/code&gt; table and a few clicks in the admin UI. No code change required.&lt;/p&gt;

&lt;h3&gt;
  
  
  Why bundling matters
&lt;/h3&gt;

&lt;p&gt;You can build all of this yourself. Here's the realistic timeline I've seen in startups:&lt;/p&gt;

&lt;div class="table-wrapper-paragraph"&gt;&lt;table&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th&gt;Component&lt;/th&gt;
&lt;th&gt;Time to build properly (mid-senior engineer)&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;DB schema + migrations&lt;/td&gt;
&lt;td&gt;4-6 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Middleware Go + Node&lt;/td&gt;
&lt;td&gt;6-10 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;React hooks + Context&lt;/td&gt;
&lt;td&gt;4-6 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;code&gt;&amp;lt;Can&amp;gt;&lt;/code&gt; + &lt;code&gt;&amp;lt;RoleGuard&amp;gt;&lt;/code&gt; with edge cases&lt;/td&gt;
&lt;td&gt;6-10 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;code&gt;&amp;lt;PermissionMatrix&amp;gt;&lt;/code&gt; admin UI&lt;/td&gt;
&lt;td&gt;16-24 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;code&gt;&amp;lt;UserRolesEditor&amp;gt;&lt;/code&gt; with search/pagination&lt;/td&gt;
&lt;td&gt;8-16 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;
&lt;code&gt;&amp;lt;AuditLogViewer&amp;gt;&lt;/code&gt; with filters/export&lt;/td&gt;
&lt;td&gt;12-20 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Audit middleware + before/after snapshot logic&lt;/td&gt;
&lt;td&gt;8-12 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;End-to-end tests, documentation, bugfixes&lt;/td&gt;
&lt;td&gt;16-24 hours&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;&lt;strong&gt;Total realistic&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;80-130 hours (2-3 weeks)&lt;/strong&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;/div&gt;

&lt;p&gt;That's not counting design iterations, the inevitable "wait, we forgot about row-level permissions" mid-sprint, or onboarding a new engineer who needs to understand all of it.&lt;/p&gt;

&lt;p&gt;Dashforge ships it all on day 1, in your repo, code you own. You modify it freely. There's no SaaS subscription, no vendor lock-in, no monthly fee. Buy it once, deploy it forever.&lt;/p&gt;

&lt;h3&gt;
  
  
  How it composes with the rest of the kit
&lt;/h3&gt;

&lt;p&gt;The checkout-kit isn't just RBAC. The same auth + permission layer also powers:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Stripe checkout flow&lt;/strong&gt; — pricing tiers gated by role (admin sees test-mode toggles, customer sees buy CTAs only)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Product catalog&lt;/strong&gt; — sales can create products, customer can only browse&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Order management&lt;/strong&gt; — full CRUD for admin/sales, read-only for customer&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Multi-tenant ready&lt;/strong&gt; — extend the policy with a &lt;code&gt;tenant_id&lt;/code&gt; column and you have row-level security&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Stripe webhook handlers&lt;/strong&gt; — already protected with API-key auth, audit logged&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;The whole thing is one repo, one auth model, one permission set. Not five disconnected libraries glued together with hope.&lt;/p&gt;

&lt;p&gt;If you're about to start building this from scratch — pause and take a look at &lt;a href="https://dashforge-ui.com" rel="noopener noreferrer"&gt;the kit&lt;/a&gt;. You'll save 2-3 weeks of work and get a layer that's already been thought through. Drop a comment if you want me to share more on a specific piece (the schema migrations, the audit log middleware, the admin UI patterns).&lt;/p&gt;

&lt;h2&gt;
  
  
  Your turn
&lt;/h2&gt;

&lt;p&gt;If you've shipped RBAC in production recently, I'd love to hear what tradeoffs you made:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Did you build from scratch, or use a library (Casbin, Oso, Permify)?&lt;/li&gt;
&lt;li&gt;ABAC, ReBAC, or plain RBAC + audit?&lt;/li&gt;
&lt;li&gt;What's the one thing you'd do differently?&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Drop a comment — I'm collecting patterns for a follow-up piece on RBAC at scale (10K+ users, multi-tenant).&lt;/p&gt;




&lt;p&gt;&lt;em&gt;If you found this useful and want more deep-dives on Go/Node infrastructure patterns for startups, follow me here on dev.to.&lt;/em&gt;&lt;/p&gt;

</description>
      <category>architecture</category>
      <category>go</category>
      <category>node</category>
      <category>security</category>
    </item>
    <item>
      <title>I've built Stripe checkout from scratch 3 times. Here's what no one tells you.</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Tue, 16 Jun 2026 08:19:44 +0000</pubDate>
      <link>https://dev.to/kensaadi/ive-built-stripe-checkout-from-scratch-3-times-heres-what-no-one-tells-you-16d4</link>
      <guid>https://dev.to/kensaadi/ive-built-stripe-checkout-from-scratch-3-times-heres-what-no-one-tells-you-16d4</guid>
      <description>&lt;p&gt;Every time a client needs an e-commerce feature, the conversation starts the same way.&lt;/p&gt;

&lt;p&gt;&lt;em&gt;"We need Stripe checkout. How long?"&lt;/em&gt;&lt;br&gt;
And every time I say two months, they look at me like I'm padding the estimate.&lt;/p&gt;

&lt;p&gt;I'm not.&lt;/p&gt;

&lt;p&gt;Here's what's actually hiding inside "just add Stripe checkout."&lt;/p&gt;


&lt;h2&gt;
  
  
  1. The cart is not a frontend problem
&lt;/h2&gt;

&lt;p&gt;The instinct is to keep cart state in React. &lt;code&gt;useState&lt;/code&gt;, maybe Zustand, done in an afternoon.&lt;/p&gt;

&lt;p&gt;Then your user adds items on desktop, opens their phone, and the cart is empty.&lt;/p&gt;

&lt;p&gt;A production cart lives on the server. Every add/remove/update hits an API. The frontend is a view, not the source of truth. That's a full Mongoose model, a set of CRUD endpoints, and session-aware middleware — before you've touched Stripe at all.&lt;/p&gt;


&lt;h2&gt;
  
  
  2. Stripe SCA is not Stripe Checkout
&lt;/h2&gt;

&lt;p&gt;SCA (Strong Customer Authentication) is mandatory in Europe and increasingly common everywhere. It means the payment flow isn't a single redirect — it's a multi-step confirmation that your frontend has to handle gracefully.&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;paymentIntent&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;stripe&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;paymentIntents&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;create&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt;
  &lt;span class="na"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;orderTotal&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="na"&gt;currency&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;usd&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="na"&gt;automatic_payment_methods&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;enabled&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt; &lt;span class="p"&gt;},&lt;/span&gt;
&lt;span class="p"&gt;});&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Then on the client, you're handling &lt;code&gt;requires_action&lt;/code&gt;, &lt;code&gt;requires_payment_method&lt;/code&gt;, and &lt;code&gt;succeeded&lt;/code&gt; states separately. Each one needs a different UI path.&lt;/p&gt;




&lt;h2&gt;
  
  
  3. Webhooks are where things break in production
&lt;/h2&gt;

&lt;p&gt;The payment succeeded on the client. Great. But your server doesn't know yet.&lt;/p&gt;

&lt;p&gt;Webhooks are how Stripe tells your backend what actually happened — and they arrive asynchronously, out of order, and sometimes more than once.&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;event&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;stripe&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;webhooks&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;constructEvent&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="nx"&gt;req&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;body&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nx"&gt;req&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;headers&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;stripe-signature&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
  &lt;span class="nx"&gt;process&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;env&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;STRIPE_WEBHOOK_SECRET&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="k"&gt;switch &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;event&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;payment_intent.succeeded&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
    &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;fulfillOrder&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;event&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;object&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="k"&gt;break&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;charge.refunded&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
    &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;handleRefund&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;event&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;object&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="k"&gt;break&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;You need idempotency handling, signature verification, and a clear fulfillment model. Miss any of these and you'll have orders that paid but never confirmed — or confirmed twice.&lt;/p&gt;




&lt;h2&gt;
  
  
  4. Order management is a separate product
&lt;/h2&gt;

&lt;p&gt;Once the payment goes through, you need:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;A customer view (what did I order, what's the status)&lt;/li&gt;
&lt;li&gt;An admin view (filter all orders, update status, process refunds)&lt;/li&gt;
&lt;li&gt;Status transitions that make sense (pending → paid → shipped → delivered)&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;That's two full UIs and a state machine. Not complex — but a lot of screens.&lt;/p&gt;




&lt;h2&gt;
  
  
  5. The admin dashboard needs RBAC from day one
&lt;/h2&gt;

&lt;p&gt;Without role-based access control, your admin routes are either wide open or you're scattering &lt;code&gt;if (user.isAdmin)&lt;/code&gt; checks across the codebase. Neither scales.&lt;/p&gt;

&lt;p&gt;A proper RBAC middleware layer means routes declare what they need and middleware enforces it:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="nx"&gt;router&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;get&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;/admin/orders&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nx"&gt;authenticate&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nf"&gt;requireRole&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;admin&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;sales&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
  &lt;span class="nx"&gt;OrderController&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;getAll&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Three roles minimum: &lt;code&gt;public&lt;/code&gt;, &lt;code&gt;customer&lt;/code&gt;, &lt;code&gt;admin&lt;/code&gt;. Adding more later is trivial when the pattern is in place from the start.&lt;/p&gt;




&lt;h2&gt;
  
  
  6. S3 image upload is a full integration on its own
&lt;/h2&gt;

&lt;p&gt;Product images need to live somewhere. That means presigned URLs, upload from the admin form, and references stored in MongoDB. Works with AWS S3 or DigitalOcean Spaces — but either way it's a separate surface to wire correctly.&lt;/p&gt;




&lt;h2&gt;
  
  
  What this actually adds up to
&lt;/h2&gt;

&lt;p&gt;Every time I've built this stack from scratch, it's taken 6–8 weeks for a senior developer. Not because any single piece is hard — because there are multiple pieces and they all have to work together correctly in production.&lt;/p&gt;

&lt;p&gt;After doing it for the third time, I packaged everything into a kit.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Checkout Kit&lt;/strong&gt; ships with:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;React 19 frontend — MUI and Tailwind flavors, both included&lt;/li&gt;
&lt;li&gt;Go or Node backend — same API contracts, your choice of runtime&lt;/li&gt;
&lt;li&gt;MongoDB, Mongoose, JWT + bcrypt&lt;/li&gt;
&lt;li&gt;All 6 surfaces above, already wired together&lt;/li&gt;
&lt;li&gt;Mock mode for full frontend dev without a running server&lt;/li&gt;
&lt;li&gt;17+ production screens, 35+ API endpoints&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Setup to first live checkout: under 15 minutes.&lt;/p&gt;

&lt;p&gt;Live demo (no signup): &lt;a href="https://checkout-kit.dashforge-ui.com" rel="noopener noreferrer"&gt;https://checkout-kit.dashforge-ui.com&lt;/a&gt;&lt;br&gt;
Full details: &lt;a href="https://dashforge-ui.com/starter-kits/checkout-kit" rel="noopener noreferrer"&gt;https://dashforge-ui.com/starter-kits/checkout-kit&lt;/a&gt;&lt;/p&gt;




&lt;h2&gt;
  
  
  Free for the first 5 developers who want to try it
&lt;/h2&gt;

&lt;p&gt;I'm giving the Developer tier away free to the first 5 developers who want to try it.&lt;/p&gt;

&lt;p&gt;Try it. Then leave an honest comment with your impressions — what worked, what didn't. No star ratings, no forms. Just real feedback from a real developer.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Comment "interested" below and I'll DM you the link.&lt;/strong&gt;&lt;/p&gt;

</description>
      <category>webdev</category>
      <category>react</category>
      <category>go</category>
      <category>stripe</category>
    </item>
    <item>
      <title>Back to React Fundamentals: useEffect, useState, useMemo, useCallback, useReducer</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Sat, 09 May 2026 20:06:01 +0000</pubDate>
      <link>https://dev.to/kensaadi/back-to-react-fundamentals-useeffect-usestate-usememo-usecallback-usereducer-4mk1</link>
      <guid>https://dev.to/kensaadi/back-to-react-fundamentals-useeffect-usestate-usememo-usecallback-usereducer-4mk1</guid>
      <description>&lt;p&gt;&lt;strong&gt;Updated for React 19.2 (2025)&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Over the last few years, the React ecosystem has become increasingly complex.&lt;/p&gt;

&lt;p&gt;Server Components, compilers, signals, state managers, meta-frameworks, cache layers, streaming, optimistic UI.&lt;/p&gt;

&lt;p&gt;But while everyone is chasing the next big thing, many real-world React problems still come from the same places:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;poorly used useEffect&lt;/li&gt;
&lt;li&gt;misunderstood dependencies&lt;/li&gt;
&lt;li&gt;unnecessary re-renders&lt;/li&gt;
&lt;li&gt;premature memoization&lt;/li&gt;
&lt;li&gt;oversized components&lt;/li&gt;
&lt;li&gt;badly distributed state&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;This article is a return to fundamentals.&lt;/p&gt;

&lt;p&gt;Not theoretical concepts, but the things that truly matter when building scalable and maintainable React applications.&lt;/p&gt;




&lt;h2&gt;
  
  
  Latest: React 19.2 Release (October 2025)
&lt;/h2&gt;

&lt;p&gt;&lt;strong&gt;Concurrent rendering&lt;/strong&gt; was introduced in React 18 via &lt;code&gt;createRoot&lt;/code&gt;, not React 19.&lt;/p&gt;

&lt;p&gt;React 19.2 adds several important features:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;&lt;code&gt;useEffectEvent&lt;/code&gt;&lt;/strong&gt; — Separate reactive from non-reactive logic in effects&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;&lt;code&gt;&amp;lt;Activity /&amp;gt;&lt;/code&gt;&lt;/strong&gt; — Hide and restore UI sections with independent state management&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;&lt;code&gt;cacheSignal&lt;/code&gt;&lt;/strong&gt; — Know when server component cache lifetime is over (RSCs only)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Performance Tracks&lt;/strong&gt; — New Chrome DevTools performance profiling&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Partial Pre-rendering&lt;/strong&gt; — Pre-render static parts and resume with dynamic content later&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Key insight&lt;/strong&gt;: These features build on the fundamentals below. Master state colocation, dependency management, and component splitting first—then layer in React 19's advanced capabilities.&lt;/p&gt;




&lt;h2&gt;
  
  
  First rule: React renders functions
&lt;/h2&gt;

&lt;p&gt;When a React component updates:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;the component function runs again&lt;/li&gt;
&lt;li&gt;all hooks run again&lt;/li&gt;
&lt;li&gt;objects and functions declared inside are recreated&lt;/li&gt;
&lt;li&gt;React performs reconciliation to identify what actually changed&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Example:
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Counter&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Counter render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Every click:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;re-executes Counter&lt;/li&gt;
&lt;li&gt;recreates the onClick function&lt;/li&gt;
&lt;li&gt;reevaluates the JSX&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;This is completely normal.&lt;/p&gt;

&lt;p&gt;The real problem starts when:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;the component becomes huge&lt;/li&gt;
&lt;li&gt;it contains too much logic&lt;/li&gt;
&lt;li&gt;it renders expensive children&lt;/li&gt;
&lt;li&gt;it passes unstable props&lt;/li&gt;
&lt;li&gt;it centralizes too much state&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;And this leads us to the first truly important concept.&lt;/p&gt;

&lt;h2&gt;
  
  
  Splitting code into components
&lt;/h2&gt;

&lt;p&gt;One of the most powerful ways to optimize React is not useMemo.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;It's splitting components correctly.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;The most common mistake is putting too much state and UI inside the same component.&lt;/p&gt;

&lt;h3&gt;
  
  
  Problematic example
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Dashboard&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Dashboard render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
        Increment: &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;

      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;ExpensiveChart&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;ComplexTable&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;HeavySidebar&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ExpensiveChart&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;ExpensiveChart render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Chart&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ComplexTable&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;ComplexTable render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Table&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;HeavySidebar&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;HeavySidebar render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Sidebar&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Every click updates the state of Dashboard.&lt;/p&gt;

&lt;p&gt;As a consequence:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Dashboard re-runs&lt;/li&gt;
&lt;li&gt;JSX is recreated&lt;/li&gt;
&lt;li&gt;child React elements are recreated&lt;/li&gt;
&lt;li&gt;React reevaluates the child tree&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;So you might see:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Dashboard render&lt;/li&gt;
&lt;li&gt;ExpensiveChart render&lt;/li&gt;
&lt;li&gt;ComplexTable render&lt;/li&gt;
&lt;li&gt;HeavySidebar render&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;even though those components do not depend on count.&lt;/p&gt;

&lt;p&gt;The issue is not the button.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;The issue is that the state lives too high in the tree.&lt;/strong&gt;&lt;/p&gt;

&lt;h3&gt;
  
  
  Solution: move state closer to where it's actually needed
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Dashboard&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Dashboard render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;CounterSection&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;

      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;ExpensiveChart&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;ComplexTable&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;HeavySidebar&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;CounterSection&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;CounterSection render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      Increment: &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ExpensiveChart&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;ExpensiveChart render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Chart&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ComplexTable&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;ComplexTable render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Table&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;HeavySidebar&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;HeavySidebar render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Sidebar&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Now when you click the button:&lt;br&gt;
 render&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;This is the crucial difference:&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;A child state update does not automatically force parent components to re-render.&lt;/p&gt;

&lt;p&gt;React starts the update from the component whose state changed and only re-renders the necessary part of the tree.&lt;/p&gt;

&lt;p&gt;Before refactoring, the state lived in Dashboard, so every click forced Dashboard to run again and recreate the child tree. All children would be re-evaluated as a result.&lt;/p&gt;

&lt;p&gt;After refactoring, the state lives inside CounterSection, so the update stays local. The state update triggers a re-render of &lt;code&gt;CounterSection&lt;/code&gt; only.&lt;/p&gt;

&lt;p&gt;Because Dashboard no longer updates, React has no reason to traverse and re-render those children. ExpensiveChart, ComplexTable, and HeavySidebar are not affected by this state change.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;This is the core principle&lt;/strong&gt;: state that affects only a small part of the UI should live in that part. Where state lives determines where reconciliation starts and what gets re-rendered.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;This is the real value of component splitting&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;You didn't use:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;useMemo&lt;/li&gt;
&lt;li&gt;useCallback&lt;/li&gt;
&lt;li&gt;React.memo&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;You simply:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;isolated responsibilities&lt;/li&gt;
&lt;li&gt;localized state&lt;/li&gt;
&lt;li&gt;reduced update propagation&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Note on React.memo:&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;React.memo has legitimate uses—wrapping expensive components that receive stable props, or protecting components that receive object/function props. But it's a second-line optimization. Component splitting solves 90% of performance problems without it.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;This is one of the most important React optimizations:&lt;/strong&gt;&lt;/p&gt;
&lt;h3&gt;
  
  
  State colocation
&lt;/h3&gt;

&lt;p&gt;Keeping state as close as possible to where it is used.&lt;/p&gt;
&lt;h3&gt;
  
  
  Practical rule
&lt;/h3&gt;

&lt;p&gt;If a piece of state only belongs to a small part of the UI, don't put it in the parent component.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Better:&lt;/strong&gt;&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Page&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Header&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;SearchBox&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Results&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;SearchBox&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;query&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setQuery&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;''&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;input&lt;/span&gt;
      &lt;span class="na"&gt;value&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;query&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
      &lt;span class="na"&gt;onChange&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;event&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setQuery&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;event&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;target&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;Worse:&lt;/strong&gt;&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Page&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;query&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setQuery&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;''&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Header&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;SearchBox&lt;/span&gt;
        &lt;span class="na"&gt;query&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;query&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
        &lt;span class="na"&gt;setQuery&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;setQuery&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
      &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Results&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;In the second example, every keystroke may rerun the entire Page.&lt;/p&gt;

&lt;p&gt;In the first one, the update stays local.&lt;/p&gt;

&lt;h2&gt;
  
  
  Component splitting vs Lazy Loading
&lt;/h2&gt;

&lt;p&gt;These two concepts are often confused.&lt;/p&gt;

&lt;p&gt;But they solve completely different problems.&lt;/p&gt;

&lt;h3&gt;
  
  
  Component Splitting
&lt;/h3&gt;

&lt;p&gt;Used for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;isolating responsibilities&lt;/li&gt;
&lt;li&gt;limiting state propagation&lt;/li&gt;
&lt;li&gt;improving maintainability&lt;/li&gt;
&lt;li&gt;making renders more predictable&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Lazy Loading
&lt;/h3&gt;

&lt;p&gt;Used for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;loading code only when needed&lt;/li&gt;
&lt;li&gt;reducing the initial bundle size&lt;/li&gt;
&lt;li&gt;improving initial loading performance&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Example:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;AdminPage&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;lazy&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="k"&gt;import&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;./AdminPage&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This does NOT optimize renders.&lt;/p&gt;

&lt;p&gt;It optimizes bundle downloading.&lt;/p&gt;

&lt;h2&gt;
  
  
  useState: values vs references
&lt;/h2&gt;

&lt;p&gt;Before truly understanding useEffect, you need to understand something fundamental:&lt;/p&gt;

&lt;p&gt;in JavaScript there are:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;primitive values&lt;/li&gt;
&lt;li&gt;references&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Primitive values
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;a&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;a&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt; &lt;span class="c1"&gt;// true&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Objects and arrays
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;a&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Ken&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;};&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Ken&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;};&lt;/span&gt;

&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;a&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt; &lt;span class="c1"&gt;// false&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Why?&lt;/p&gt;

&lt;p&gt;Because JavaScript compares memory references.&lt;/p&gt;

&lt;p&gt;Not contents.&lt;/p&gt;

&lt;p&gt;This concept is &lt;strong&gt;ESSENTIAL&lt;/strong&gt; for understanding:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;useEffect&lt;/li&gt;
&lt;li&gt;useMemo&lt;/li&gt;
&lt;li&gt;useCallback&lt;/li&gt;
&lt;li&gt;React.memo&lt;/li&gt;
&lt;li&gt;re-renders&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  useEffect: it's not really componentDidMount
&lt;/h2&gt;

&lt;p&gt;Many developers still think of useEffect as:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;componentDidMount&lt;/li&gt;
&lt;li&gt;componentDidUpdate&lt;/li&gt;
&lt;li&gt;componentWillUnmount&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;It's a useful beginner mental model.&lt;/p&gt;

&lt;p&gt;But it's not what useEffect truly is.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;useEffect exists to synchronize React with the outside world.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Examples:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;APIs&lt;/li&gt;
&lt;li&gt;timers&lt;/li&gt;
&lt;li&gt;websockets&lt;/li&gt;
&lt;li&gt;localStorage&lt;/li&gt;
&lt;li&gt;browser events&lt;/li&gt;
&lt;li&gt;analytics&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  useEffect equivalent to didMount
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;mounted&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The empty dependency array means:&lt;/p&gt;

&lt;p&gt;run the effect only on mount.&lt;/p&gt;

&lt;h3&gt;
  
  
  Real-world example: API call on mount
&lt;/h3&gt;

&lt;p&gt;For fetch-on-mount scenarios, the &lt;strong&gt;nested function pattern is the modern best practice&lt;/strong&gt;:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;UsersPage&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setUsers&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;([]);&lt;/span&gt;

  &lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;loadUsers&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;response&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;fetch&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;/api/users&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;data&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;response&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;json&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

      &lt;span class="nf"&gt;setUsers&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;

    &lt;span class="nf"&gt;loadUsers&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;UsersTable&lt;/span&gt; &lt;span class="na"&gt;users&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;Why this pattern?&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;The function is defined &lt;em&gt;inside&lt;/em&gt; useEffect, so it doesn't need to be a dependency&lt;/li&gt;
&lt;li&gt;No memoization overhead&lt;/li&gt;
&lt;li&gt;Simpler and more readable&lt;/li&gt;
&lt;li&gt;The function is isolated to where it's actually used&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  When you DO need useCallback with useEffect
&lt;/h3&gt;

&lt;p&gt;Only reach for useCallback when loadUsers needs to be &lt;strong&gt;called elsewhere or exposed as a stable reference&lt;/strong&gt;:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;UsersPage&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setUsers&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;([]);&lt;/span&gt;

  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;loadUsers&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useCallback&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;response&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;fetch&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;/api/users&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;data&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;response&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;json&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

    &lt;span class="nf"&gt;setUsers&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;

  &lt;span class="c1"&gt;// ✅ Use useCallback here because:&lt;/span&gt;
  &lt;span class="c1"&gt;// - loadUsers is a dependency of useEffect&lt;/span&gt;
  &lt;span class="c1"&gt;// - loadUsers is passed as a prop to child components&lt;/span&gt;
  &lt;span class="c1"&gt;// - loadUsers might be called from multiple places&lt;/span&gt;

  &lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;loadUsers&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;loadUsers&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;RefreshButton&lt;/span&gt; &lt;span class="na"&gt;onRefresh&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;loadUsers&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;UsersTable&lt;/span&gt; &lt;span class="na"&gt;users&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;The key difference:&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Nested function&lt;/strong&gt;: Simpler, no memoization. Use when the function only belongs inside useEffect.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;useCallback&lt;/strong&gt;: Overhead, but necessary when the function is a dependency or needs to be stable across renders.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Default approach&lt;/strong&gt;: Start with the nested function. Only add useCallback if you actually need a stable reference.&lt;/p&gt;

&lt;h3&gt;
  
  
  Why you should NOT use async directly in useEffect
&lt;/h3&gt;

&lt;p&gt;Common mistake:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="c1"&gt;// NO&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Because useEffect expects:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;void&lt;/li&gt;
&lt;li&gt;or a cleanup function&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;An async function always returns a Promise.&lt;/p&gt;

&lt;h3&gt;
  
  
  Cleanup function
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;interval&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;setInterval&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;tick&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="mi"&gt;1000&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;clearInterval&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;interval&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;};&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The cleanup function runs:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;on unmount&lt;/li&gt;
&lt;li&gt;before the next effect execution&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  useEffect as didUpdate
&lt;/h3&gt;

&lt;h4&gt;
  
  
  Single dependency
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;count changed&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The effect runs when count changes.&lt;/p&gt;

&lt;h4&gt;
  
  
  Multiple dependencies
&lt;/h4&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;filters changed&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;search&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;page&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;sort&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;It runs whenever at least one dependency changes.&lt;/p&gt;

&lt;h4&gt;
  
  
  Object dependencies
&lt;/h4&gt;

&lt;p&gt;This is where many real-world problems begin.&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;filters&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;search&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nx"&gt;page&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
&lt;span class="p"&gt;};&lt;/span&gt;

&lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;filters changed&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;filters&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This effect will run &lt;strong&gt;EVERY render&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;Why?&lt;/p&gt;

&lt;p&gt;Because the object is recreated every render.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Solution with useMemo&lt;/strong&gt;&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;filters&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useMemo&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nx"&gt;search&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;page&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="p"&gt;};&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;search&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;page&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Now the reference stays stable.&lt;/p&gt;

&lt;h2&gt;
  
  
  useMemo: when to actually use it
&lt;/h2&gt;

&lt;p&gt;useMemo is NOT for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;"optimizing React"&lt;/li&gt;
&lt;li&gt;"avoiding renders"&lt;/li&gt;
&lt;li&gt;"making everything faster"&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;It's for memoizing expensive values or stabilizing references.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Important&lt;/strong&gt;: useMemo is a performance optimization hint, not a semantic guarantee. React may discard memoized values in some scenarios, especially during development, concurrent rendering, or future internal optimizations. Never depend on memoization for correctness—only for performance.&lt;/p&gt;

&lt;h3&gt;
  
  
  Correct use case
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;sortedUsers&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useMemo&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;[...&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="p"&gt;].&lt;/span&gt;&lt;span class="nf"&gt;sort&lt;/span&gt;&lt;span class="p"&gt;((&lt;/span&gt;&lt;span class="nx"&gt;a&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt;
    &lt;span class="nx"&gt;a&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;localeCompare&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This makes sense because:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;sorting may be expensive&lt;/li&gt;
&lt;li&gt;the result gets reused&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  WRONG use case
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;fullName&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useMemo&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="s2"&gt;`&lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt; &lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;surname&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt;`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;surname&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The cost here is irrelevant.&lt;/p&gt;

&lt;p&gt;You added unnecessary complexity.&lt;/p&gt;

&lt;h3&gt;
  
  
  The problem with memoizing everything
&lt;/h3&gt;

&lt;p&gt;Many modern React projects look like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;useMemo&lt;/span&gt;&lt;span class="p"&gt;(...)&lt;/span&gt;
&lt;span class="nf"&gt;useCallback&lt;/span&gt;&lt;span class="p"&gt;(...)&lt;/span&gt;
&lt;span class="nf"&gt;useMemo&lt;/span&gt;&lt;span class="p"&gt;(...)&lt;/span&gt;
&lt;span class="nf"&gt;useCallback&lt;/span&gt;&lt;span class="p"&gt;(...)&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;everywhere.&lt;/p&gt;

&lt;p&gt;This often worsens:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;readability&lt;/li&gt;
&lt;li&gt;debugging&lt;/li&gt;
&lt;li&gt;maintainability&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;And introduces mental overhead.&lt;/p&gt;

&lt;h3&gt;
  
  
  Important truth
&lt;/h3&gt;

&lt;p&gt;&lt;strong&gt;If your code is properly split:&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;most of the time you do NOT need useMemo.&lt;/p&gt;

&lt;h2&gt;
  
  
  useCallback
&lt;/h2&gt;

&lt;p&gt;useCallback memoizes a function.&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;handleClick&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useCallback&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;click&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;It is mainly useful when:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;passing callbacks to memoized children&lt;/li&gt;
&lt;li&gt;reference stability matters&lt;/li&gt;
&lt;li&gt;the function is a dependency of an effect&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  The real difference between &lt;code&gt;&amp;lt;Component /&amp;gt;&lt;/code&gt; and &lt;code&gt;{component}&lt;/code&gt;
&lt;/h2&gt;

&lt;p&gt;This is one of the least understood parts of React.&lt;/p&gt;

&lt;p&gt;Many developers think:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;and:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;child&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;are equivalent.&lt;/p&gt;

&lt;p&gt;They are not.&lt;/p&gt;

&lt;p&gt;The difference depends on &lt;strong&gt;WHERE the React element is created.&lt;/strong&gt;&lt;/p&gt;

&lt;h3&gt;
  
  
  Case 1 — &lt;code&gt;&amp;lt;Child /&amp;gt;&lt;/code&gt; inside render
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Child&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Child render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Child&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Parent&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
        Increment
      &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;

      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Every update of Parent:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;reruns Parent&lt;/li&gt;
&lt;li&gt;recreates &lt;code&gt;&amp;lt;Child /&amp;gt;&lt;/code&gt;
&lt;/li&gt;
&lt;li&gt;React reevaluates the child&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;So:&lt;/p&gt;

&lt;h2&gt;
  
  
  Child render
&lt;/h2&gt;

&lt;p&gt;appears on every click.&lt;/p&gt;

&lt;h3&gt;
  
  
  Case 2 — React element stabilized outside the component
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;child&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Child&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Child render&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Child&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Parent&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setCount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
        Increment
      &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;

      &lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;child&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Here:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;child is created only once&lt;/li&gt;
&lt;li&gt;the reference stays stable&lt;/li&gt;
&lt;li&gt;React always receives the same element&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;So Child &lt;strong&gt;does NOT rerun every parent render&lt;/strong&gt;.&lt;/p&gt;

&lt;h3&gt;
  
  
  Case 3 — Variable inside render
&lt;/h3&gt;

&lt;p&gt;Many developers do this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Parent&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;child&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;

  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;child&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;But this changes &lt;strong&gt;NOTHING&lt;/strong&gt; compared to:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Because:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;child&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;runs again every render.&lt;/p&gt;

&lt;p&gt;So:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;new React element&lt;/li&gt;
&lt;li&gt;new reference&lt;/li&gt;
&lt;li&gt;new reconciliation&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  React element vs Component Function
&lt;/h3&gt;

&lt;p&gt;This is the key concept.&lt;/p&gt;

&lt;p&gt;This:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Child&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;is NOT the component itself.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;It's a React element.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;An object similar to:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="na"&gt;type&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;Child&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="na"&gt;props&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;When React receives a new element:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;it decides whether to render&lt;/li&gt;
&lt;li&gt;compares the tree&lt;/li&gt;
&lt;li&gt;performs reconciliation&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Very common pattern: passing React elements as props
&lt;/h3&gt;

&lt;p&gt;Many modern UI systems use this pattern:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Layout&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;sidebar&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;aside&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;sidebar&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;aside&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;main&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Content&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;main&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;div&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Usage:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;sidebar&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Sidebar&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;App&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Layout&lt;/span&gt; &lt;span class="na"&gt;sidebar&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;sidebar&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Here sidebar remains stable.&lt;/p&gt;

&lt;p&gt;If App rerenders:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;React receives the same React element&lt;/li&gt;
&lt;li&gt;Sidebar may avoid unnecessary rerenders&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  But be careful
&lt;/h3&gt;

&lt;p&gt;Do NOT overuse this pattern.&lt;/p&gt;

&lt;p&gt;Because it may:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;hurt readability&lt;/li&gt;
&lt;li&gt;create unexpected behavior&lt;/li&gt;
&lt;li&gt;make the component tree less natural&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Stabilizing React elements outside render is an advanced optimization pattern. In most applications, proper component splitting and state colocation are significantly more important.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Most of the time:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nc"&gt;Sidebar&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;is perfectly fine.&lt;/p&gt;

&lt;h2&gt;
  
  
  The real React optimization
&lt;/h2&gt;

&lt;p&gt;Modern React optimization is about:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;small components&lt;/li&gt;
&lt;li&gt;localized state&lt;/li&gt;
&lt;li&gt;stable props&lt;/li&gt;
&lt;li&gt;simple architecture&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Not:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;useMemo everywhere&lt;/li&gt;
&lt;li&gt;or &lt;code&gt;const child = &amp;lt;Child /&amp;gt;&lt;/code&gt; everywhere&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  useReducer
&lt;/h2&gt;

&lt;p&gt;useReducer is one of the most underrated React hooks.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;It is NOT Redux&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Many developers associate it with Redux.&lt;/p&gt;

&lt;p&gt;But useReducer is simply:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;local state management&lt;/li&gt;
&lt;li&gt;reducer-based logic&lt;/li&gt;
&lt;li&gt;excellent for complex flows&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Basic syntax
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;initialState&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="na"&gt;count&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
&lt;span class="p"&gt;};&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;reducer&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;switch &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;increment&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="p"&gt;...&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;count&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
      &lt;span class="p"&gt;};&lt;/span&gt;

    &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;decrement&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="p"&gt;...&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;count&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
      &lt;span class="p"&gt;};&lt;/span&gt;

    &lt;span class="nl"&gt;default&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Usage:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;dispatch&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useReducer&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="nx"&gt;reducer&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nx"&gt;initialState&lt;/span&gt;
&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Dispatch
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="nf"&gt;dispatch&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="na"&gt;type&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;increment&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;});&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  When to prefer useReducer
&lt;/h3&gt;

&lt;p&gt;useState is perfect for simple state:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;open&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setOpen&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;But when you start having:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;multiple related states&lt;/li&gt;
&lt;li&gt;complex transitions&lt;/li&gt;
&lt;li&gt;dependent updates&lt;/li&gt;
&lt;li&gt;multi-step flows&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;useReducer becomes much clearer.&lt;/p&gt;

&lt;h3&gt;
  
  
  Real-world example: fetch state
&lt;/h3&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;initialState&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="na"&gt;loading&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="na"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
&lt;span class="p"&gt;};&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Reducer:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;reducer&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;switch &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;fetch_start&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="p"&gt;...&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;loading&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
      &lt;span class="p"&gt;};&lt;/span&gt;

    &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;fetch_success&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="na"&gt;loading&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;payload&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
      &lt;span class="p"&gt;};&lt;/span&gt;

    &lt;span class="k"&gt;case&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;fetch_error&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="na"&gt;loading&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
        &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;action&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;payload&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
      &lt;span class="p"&gt;};&lt;/span&gt;

    &lt;span class="nl"&gt;default&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Here useReducer makes the flow:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;more readable&lt;/li&gt;
&lt;li&gt;more predictable&lt;/li&gt;
&lt;li&gt;more scalable&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  React 19 &amp;amp; Beyond: Building on Fundamentals
&lt;/h2&gt;

&lt;p&gt;React 19 introduces powerful new features. React 19.2 adds more. But they all build on the fundamentals covered above.&lt;/p&gt;

&lt;h3&gt;
  
  
  Server Actions (React 19)
&lt;/h3&gt;

&lt;p&gt;Server Actions simplify async workflows through functions marked with &lt;code&gt;'use server'&lt;/code&gt;:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;use server&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;updateUser&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;result&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;db&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;users&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;update&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="nf"&gt;revalidatePath&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;/users&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;result&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Used in a component:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;UserForm&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;isPending&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;startTransition&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useTransition&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;form&lt;/span&gt; &lt;span class="na"&gt;action&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;updateUser&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;input&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"email"&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;type&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"submit"&lt;/span&gt; &lt;span class="na"&gt;disabled&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;isPending&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
        Save
      &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;form&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;Why fundamentals apply&lt;/strong&gt;: Even with Server Actions, you're managing state colocation (isPending stays local), understanding dependencies, and avoiding unnecessary re-renders (React handles submission state automatically).&lt;/p&gt;

&lt;h3&gt;
  
  
  useActionState &amp;amp; useOptimistic (React 19)
&lt;/h3&gt;

&lt;p&gt;React 19 introduces &lt;code&gt;useActionState&lt;/code&gt; for form submissions and &lt;code&gt;useOptimistic&lt;/code&gt; for optimistic updates:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Todo&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;optimisticTodos&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;addOptimisticTodo&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useOptimistic&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;todos&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;formState&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;formAction&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useActionState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;addTodoAction&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;form&lt;/span&gt; &lt;span class="na"&gt;action&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="nf"&gt;addOptimisticTodo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;get&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;todo&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt;
      &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;formAction&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;input&lt;/span&gt; &lt;span class="na"&gt;name&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"todo"&lt;/span&gt; &lt;span class="p"&gt;/&amp;gt;&lt;/span&gt;
      &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;type&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="s"&gt;"submit"&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;Add&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
    &lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;form&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;Why fundamentals apply&lt;/strong&gt;: These APIs handle the complex state management patterns you'd normally need &lt;code&gt;useReducer&lt;/code&gt; or &lt;code&gt;useState&lt;/code&gt; for—but they're built on the same dependency and state management principles.&lt;/p&gt;

&lt;h3&gt;
  
  
  useEffectEvent (React 19.2)
&lt;/h3&gt;

&lt;p&gt;&lt;code&gt;useEffectEvent&lt;/code&gt; separates reactive from non-reactive logic in effects, formalizing a core concept:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ChatRoom&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;roomId&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;theme&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;onConnected&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useEffectEvent&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;showNotification&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Connected!&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;theme&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;});&lt;/span&gt;

  &lt;span class="nf"&gt;useEffect&lt;/span&gt;&lt;span class="p"&gt;(()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;connection&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;createConnection&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;serverUrl&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;roomId&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="nx"&gt;connection&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;on&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;connected&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="nf"&gt;onConnected&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
    &lt;span class="p"&gt;});&lt;/span&gt;
    &lt;span class="nx"&gt;connection&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;connect&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
    &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nx"&gt;connection&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;disconnect&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;roomId&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt; &lt;span class="c1"&gt;// ✅ theme is NOT a dependency&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;&lt;strong&gt;Why fundamentals apply&lt;/strong&gt;: This hook encodes a principle you already understand—effects depend on specific values (roomId matters), and non-reactive logic shouldn't trigger re-effects. Dependencies matter; this hook just makes it explicit.&lt;/p&gt;

&lt;h3&gt;
  
  
  &lt;code&gt;&amp;lt;Activity /&amp;gt;&lt;/code&gt; (React 19.2)
&lt;/h3&gt;

&lt;p&gt;The Activity component allows sections of the UI tree to be paused, hidden, and resumed independently:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Activity&lt;/span&gt; &lt;span class="nx"&gt;mode&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;isVisible&lt;/span&gt; &lt;span class="p"&gt;?&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;visible&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;hidden&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Page&lt;/span&gt; &lt;span class="o"&gt;/&amp;gt;&lt;/span&gt;
&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/Activity&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;When hidden, Activity unmounts effects and defers updates. This pre-renders hidden sections without impacting visible performance.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Why fundamentals apply&lt;/strong&gt;: Activity enables fine-grained control over which parts of the tree are active, following the same principle as state colocation—isolating state and rendering to where it matters.&lt;/p&gt;

&lt;h2&gt;
  
  
  Conclusion
&lt;/h2&gt;

&lt;p&gt;Most modern React problems are not solved with:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;more libraries&lt;/li&gt;
&lt;li&gt;more abstractions&lt;/li&gt;
&lt;li&gt;more custom hooks&lt;/li&gt;
&lt;li&gt;more memoization&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;They are solved by returning to fundamentals.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Truly understanding:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;when React renders&lt;/li&gt;
&lt;li&gt;what changes by reference&lt;/li&gt;
&lt;li&gt;how dependencies work&lt;/li&gt;
&lt;li&gt;when to split components&lt;/li&gt;
&lt;li&gt;when NOT to optimize&lt;/li&gt;
&lt;li&gt;what referential stability means&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;is far more valuable than premature micro-optimizations.&lt;/p&gt;

&lt;p&gt;Because most of the time, the best React performance does not come from useMemo.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;It comes from simple architecture.&lt;/strong&gt;&lt;/p&gt;




&lt;p&gt;&lt;strong&gt;Remember&lt;/strong&gt;: The best React developers are usually not the ones using the most hooks.&lt;/p&gt;

&lt;p&gt;They are the ones building the simplest render trees.&lt;/p&gt;




&lt;p&gt;&lt;strong&gt;Article Version&lt;/strong&gt;: 2.1 (Updated October 2025 for React 19.2, with technical precision)&lt;/p&gt;

</description>
      <category>react</category>
      <category>javascript</category>
      <category>webdev</category>
      <category>frontend</category>
    </item>
    <item>
      <title># The Hidden Costs of Microfrontends — Interactive Edge Cases</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Thu, 07 May 2026 10:49:43 +0000</pubDate>
      <link>https://dev.to/kensaadi/-the-hidden-costs-of-microfrontends-interactive-edge-cases-1gl6</link>
      <guid>https://dev.to/kensaadi/-the-hidden-costs-of-microfrontends-interactive-edge-cases-1gl6</guid>
      <description>&lt;p&gt;Companion app for the article &lt;em&gt;"The Hidden Costs of Microfrontends Nobody Talks About."&lt;/em&gt;&lt;br&gt;
Six interactive demos that make the architectural failure modes of microfrontends &lt;strong&gt;visible&lt;/strong&gt;: design token drift, dependency mismatches, shared HTTP coupling, store synchronization issues, and the decision of whether to actually go distributed.&lt;/p&gt;

&lt;p&gt;No real Module Federation. No real backend. Each demo simulates two or more "microfrontends" inside a single React application so the failure modes stay legible and screenshot-friendly.&lt;/p&gt;

&lt;h2&gt;
  
  
  Why this exists
&lt;/h2&gt;

&lt;p&gt;Most microfrontend tutorials stop at loading a remote &lt;code&gt;&amp;lt;HelloWorld /&amp;gt;&lt;/code&gt;. The real problems begin when you have 5 teams, 10 microfrontends, a shared design system, drifting versions, and independent releases. This app reproduces those problems on a single laptop, in a single tab.&lt;/p&gt;

&lt;h2&gt;
  
  
  The six demos
&lt;/h2&gt;

&lt;div class="table-wrapper-paragraph"&gt;&lt;table&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th&gt;#&lt;/th&gt;
&lt;th&gt;Tab&lt;/th&gt;
&lt;th&gt;What it shows&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;1&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;Token drift&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Two MFEs with their own &lt;code&gt;tailwind.config.js&lt;/code&gt;. Different primary, different radius, different scale. Toggle to centralize.&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;2&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;Shared theme&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;The MUI counter-example: one &lt;code&gt;&amp;lt;ThemeProvider&amp;gt;&lt;/code&gt; mutated at runtime, both MFEs update in the same frame.&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;3&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;HTTP layer&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Isolated vs shared Axios, side by side. Rotate one token, push a breaking interceptor, watch the blast radius.&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;4&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;Version hell&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Mount four MFEs against a host shell. Mismatched &lt;code&gt;react&lt;/code&gt;/&lt;code&gt;@mui/material&lt;/code&gt; versions break the singleton — simulated console shows the warnings you'd see in production.&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;5&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;Shared store&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;A Zustand-style cart shared across two MFEs. Flip "version drift" and watch the singleton silently double into two ghost stores.&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;6&lt;/td&gt;
&lt;td&gt;&lt;strong&gt;Should you?&lt;/strong&gt;&lt;/td&gt;
&lt;td&gt;Six honest questions. Live recommendation: Modular Monolith / On the fence / Microfrontends.&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;/div&gt;

&lt;h2&gt;
  
  
  Stack
&lt;/h2&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Vite 5&lt;/strong&gt; — fast HMR, no config to fight&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;React 18 + TypeScript 5&lt;/strong&gt; — strict mode on&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;MUI 6&lt;/strong&gt; with &lt;code&gt;@emotion/react&lt;/code&gt; — both the app shell &lt;em&gt;and&lt;/em&gt; the "good case" in demo 2&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Plain CSS / inline styles&lt;/strong&gt; in demo 1 to mimic the Tailwind-utility divergence without dual tooling&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Run it locally
&lt;/h2&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight shell"&gt;&lt;code&gt;npm &lt;span class="nb"&gt;install
&lt;/span&gt;npm run dev      &lt;span class="c"&gt;# Vite dev server on http://localhost:5173&lt;/span&gt;
npm run build    &lt;span class="c"&gt;# tsc -b + production build&lt;/span&gt;
npm run preview  &lt;span class="c"&gt;# serve the production build&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h2&gt;
  
  
  Project layout
&lt;/h2&gt;



&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;src/
├── main.tsx
├── App.tsx                       # tabbed shell wiring the six demos
├── theme.ts                      # canonical MUI theme + design-token contract
├── components/
│   ├── DemoSection.tsx           # title + controls + takeaway wrapper
│   ├── FakeMfePane.tsx           # bordered "microfrontend" frame
│   ├── ConsoleOutput.tsx         # styled pseudo-DevTools for simulated errors
│   └── CodeBlock.tsx             # static syntax-block component
└── demos/
    ├── DesignTokenDrift.tsx
    ├── SharedThemeAdvantage.tsx
    ├── HttpLayerComparison.tsx
    ├── VersionHell.tsx
    ├── SharedStoreMinefield.tsx
    └── DecisionMatrix.tsx
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h2&gt;
  
  
  How the simulation works
&lt;/h2&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Token drift / shared theme&lt;/strong&gt; — Both MFE panes mount in the same React tree. The "isolated" demo passes a different token object to each pane; the "shared" demo wraps them in one &lt;code&gt;ThemeProvider&lt;/code&gt;. Same DOM, different sources of truth.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;HTTP layer&lt;/strong&gt; — Two in-memory client objects (one per MFE for "isolated", one global for "shared") with a fake &lt;code&gt;request()&lt;/code&gt; method. Buttons mutate &lt;code&gt;client.token&lt;/code&gt; or &lt;code&gt;client.broken&lt;/code&gt; and each pane logs what it observes.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Version hell&lt;/strong&gt; — A static table of MFE versions plus a host record. Mounting compares them and pushes simulated React / MUI warnings into the &lt;code&gt;ConsoleOutput&lt;/code&gt; component.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Shared store&lt;/strong&gt; — A tiny &lt;code&gt;FakeStore&lt;/code&gt; class with &lt;code&gt;subscribe&lt;/code&gt; / &lt;code&gt;set&lt;/code&gt;. Healthy mode: both MFE views point at the same instance. Drift mode: each points at its own instance, so increments don't cross.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;The failure modes are real even if the runtime is staged — the same code paths exist in any Module Federation setup.&lt;/p&gt;

&lt;h2&gt;
  
  
  Credits
&lt;/h2&gt;

&lt;p&gt;Article and demos by &lt;strong&gt;Ken Saadi&lt;/strong&gt;.&lt;br&gt;
&lt;a href="https://linkedin.com/in/ken-saadi" rel="noopener noreferrer"&gt;LinkedIn&lt;/a&gt; · &lt;a href="https://github.com/kensaadi/mfe-hidden-cost" rel="noopener noreferrer"&gt;repo this example&lt;/a&gt;· &lt;a href="https://kensaadi.github.io/mfe-hidden-cost/" rel="noopener noreferrer"&gt;show demo&lt;/a&gt;&lt;/p&gt;

</description>
      <category>react</category>
      <category>microfrontend</category>
      <category>architecture</category>
      <category>webdev</category>
    </item>
    <item>
      <title>Are We Overcomplicating React State? A Look at Valtio</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Sat, 02 May 2026 21:47:46 +0000</pubDate>
      <link>https://dev.to/kensaadi/are-we-overcomplicating-react-state-a-look-at-valtio-3oh1</link>
      <guid>https://dev.to/kensaadi/are-we-overcomplicating-react-state-a-look-at-valtio-3oh1</guid>
      <description>&lt;h1&gt;
  
  
  React State Feels Simple — Until It Doesn't
&lt;/h1&gt;

&lt;p&gt;React state management often feels more complex than it needs to be.&lt;/p&gt;

&lt;p&gt;Selectors, memoization, dependency arrays…&lt;br&gt;
we spend a lot of time managing &lt;em&gt;how&lt;/em&gt; state updates, not just &lt;em&gt;what&lt;/em&gt; the state is.&lt;/p&gt;

&lt;p&gt;Recently, I tried Valtio — and it made me rethink some of these patterns.&lt;/p&gt;


&lt;h2&gt;
  
  
  The usual problem
&lt;/h2&gt;

&lt;p&gt;In many React setups, especially as apps grow, state logic tends to spread:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;UI state and business state get mixed
&lt;/li&gt;
&lt;li&gt;we add selectors to control updates
&lt;/li&gt;
&lt;li&gt;we optimize re-renders manually
&lt;/li&gt;
&lt;li&gt;we introduce more abstraction to keep things under control
&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;It works — but it requires constant orchestration.&lt;/p&gt;


&lt;h2&gt;
  
  
  What felt different with Valtio
&lt;/h2&gt;

&lt;p&gt;Valtio takes a different approach based on proxies.&lt;/p&gt;

&lt;p&gt;Instead of thinking in terms of update triggers and subscriptions, you work directly with state:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;proxy&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;valtio&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;proxy&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="na"&gt;count&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt; &lt;span class="p"&gt;});&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;increment&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="o"&gt;++&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;In a component:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight tsx"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;useSnapshot&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;valtio&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;Counter&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;snap&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useSnapshot&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="na"&gt;onClick&lt;/span&gt;&lt;span class="p"&gt;=&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nx"&gt;state&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="o"&gt;++&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;&lt;/span&gt;&lt;span class="si"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;snap&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;count&lt;/span&gt;&lt;span class="si"&gt;}&lt;/span&gt;&lt;span class="p"&gt;&amp;lt;/&lt;/span&gt;&lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="p"&gt;&amp;gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;That's it.&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;No selectors &lt;/li&gt;
&lt;li&gt;No dependency arrays &lt;/li&gt;
&lt;li&gt;Minimal boilerplate &lt;/li&gt;
&lt;/ul&gt;




&lt;h2&gt;
  
  
  Why this matters
&lt;/h2&gt;

&lt;p&gt;The real benefit isn't "less code".&lt;br&gt;
It's less mental overhead.&lt;/p&gt;

&lt;p&gt;With this model:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;you don't think about when to re-render &lt;/li&gt;
&lt;li&gt;you don't orchestrate updates manually &lt;/li&gt;
&lt;li&gt;you focus on state, not the mechanics around it &lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;It feels more reactive than controlled.&lt;/p&gt;




&lt;h2&gt;
  
  
  But this doesn't remove complexity
&lt;/h2&gt;

&lt;p&gt;To be clear: complexity doesn't disappear.&lt;/p&gt;

&lt;p&gt;In real-world apps, especially with:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;dynamic forms &lt;/li&gt;
&lt;li&gt;derived state &lt;/li&gt;
&lt;li&gt;async flows &lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;you still need structure.&lt;/p&gt;

&lt;p&gt;But shifting complexity away from orchestration makes things easier to reason about.&lt;/p&gt;




&lt;h2&gt;
  
  
  Where this gets interesting
&lt;/h2&gt;

&lt;p&gt;This approach becomes even more relevant in areas like:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;complex forms (React Hook Form, MUI, etc.) &lt;/li&gt;
&lt;li&gt;dynamic UIs with dependencies between fields &lt;/li&gt;
&lt;li&gt;state that evolves frequently during development &lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;That's usually where traditional patterns start to show their limits.&lt;/p&gt;




&lt;h2&gt;
  
  
  Final thought
&lt;/h2&gt;

&lt;p&gt;Valtio won't replace every state management solution.&lt;/p&gt;

&lt;p&gt;But it challenges an important assumption:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Are we managing state… or managing the complexity around it?&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;Curious how others are approaching state management lately.&lt;/p&gt;

</description>
      <category>react</category>
      <category>javascript</category>
      <category>webdev</category>
      <category>frontend</category>
    </item>
    <item>
      <title>Stop Writing Form Glue Code: MUI Components Already Connected to React Hook Form</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Thu, 30 Apr 2026 07:53:43 +0000</pubDate>
      <link>https://dev.to/kensaadi/stop-writing-form-glue-code-mui-components-already-connected-to-react-hook-form-3k1a</link>
      <guid>https://dev.to/kensaadi/stop-writing-form-glue-code-mui-components-already-connected-to-react-hook-form-3k1a</guid>
      <description>&lt;p&gt;If you've used React Hook Form with Material UI, you know the pattern.&lt;/p&gt;

&lt;p&gt;It works well.&lt;br&gt;
It's flexible.&lt;br&gt;
But it's also… repetitive.&lt;/p&gt;

&lt;p&gt;You're not really building forms.&lt;/p&gt;
&lt;h2&gt;
  
  
  You're wiring things together.
&lt;/h2&gt;
&lt;h2&gt;
  
  
  The Pattern We All Write
&lt;/h2&gt;

&lt;p&gt;A simple input with RHF + MUI usually looks like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;Controller&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;react-hook-form&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;TextField&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;@mui/material&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Controller&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
  &lt;span class="nx"&gt;render&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{({&lt;/span&gt; &lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;fieldState&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
      &lt;span class="p"&gt;{...&lt;/span&gt;&lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
      &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
      &lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="o"&gt;!!&lt;/span&gt;&lt;span class="nx"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
      &lt;span class="nx"&gt;helperText&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;?.&lt;/span&gt;&lt;span class="nx"&gt;message&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
    &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;  &lt;span class="p"&gt;)}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Nothing wrong here.&lt;/p&gt;

&lt;p&gt;But now multiply that by:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;5 fields&lt;/li&gt;
&lt;li&gt;10 fields&lt;/li&gt;
&lt;li&gt;20 fields&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;And you start noticing something:&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;You're repeating the same integration logic over and over again.&lt;/strong&gt;&lt;/p&gt;




&lt;h2&gt;
  
  
  The Real Issue: Integration, Not the Libraries
&lt;/h2&gt;

&lt;p&gt;Material UI gives you great UI components.&lt;br&gt;
React Hook Form gives you great form state.&lt;/p&gt;

&lt;p&gt;But neither of them knows about the other.&lt;/p&gt;

&lt;p&gt;So every time, you write the glue:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;connect value / onChange&lt;/li&gt;
&lt;li&gt;map errors&lt;/li&gt;
&lt;li&gt;pass validation rules&lt;/li&gt;
&lt;li&gt;keep UI consistent&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;That glue becomes your form.&lt;/p&gt;


&lt;h2&gt;
  
  
  What If Components Already Knew RHF?
&lt;/h2&gt;

&lt;p&gt;Instead of connecting MUI to RHF manually…&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;What if your components were already connected?&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;That's what dashforge-ui does.&lt;/p&gt;

&lt;p&gt;A TextField from dashforge-ui is still visually a MUI component — but it already understands React Hook Form.&lt;/p&gt;

&lt;p&gt;So instead of this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Controller&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
  &lt;span class="nx"&gt;render&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{({&lt;/span&gt; &lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;fieldState&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt; &lt;span class="p"&gt;{...&lt;/span&gt;&lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="o"&gt;!!&lt;/span&gt;&lt;span class="nx"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;  &lt;span class="p"&gt;)}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;You write this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;TextField&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;@dashforge/ui&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Same behavior.&lt;br&gt;
Same validation.&lt;br&gt;
Same form state.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;But no glue code.&lt;/strong&gt;&lt;/p&gt;


&lt;h2&gt;
  
  
  Important: RHF Is Still There
&lt;/h2&gt;

&lt;p&gt;This is not replacing React Hook Form.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;It's built on top of it.&lt;/strong&gt;&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;form state → handled by RHF&lt;/li&gt;
&lt;li&gt;validation → handled by RHF&lt;/li&gt;
&lt;li&gt;performance → same RHF behavior&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;You're just not wiring it manually anymore.&lt;/p&gt;

&lt;p&gt;Think of it as &lt;strong&gt;RHF + MUI, already connected.&lt;/strong&gt;&lt;/p&gt;


&lt;h2&gt;
  
  
  What Changes in a Real Form
&lt;/h2&gt;
&lt;h3&gt;
  
  
  Before (RHF + MUI Vanilla)
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;useForm&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Controller&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;react-hook-form&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;TextField&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Button&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Box&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;@mui/material&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kr"&gt;interface&lt;/span&gt; &lt;span class="nx"&gt;LoginForm&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nl"&gt;email&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="nl"&gt;password&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="k"&gt;export&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;LoginForm&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;handleSubmit&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;formState&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;errors&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;useForm&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;LoginForm&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt;
    &lt;span class="na"&gt;defaultValues&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;email&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;''&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;password&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;''&lt;/span&gt; &lt;span class="p"&gt;},&lt;/span&gt;
  &lt;span class="p"&gt;});&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Box&lt;/span&gt; &lt;span class="nx"&gt;component&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;form&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt; &lt;span class="nx"&gt;onSubmit&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nf"&gt;handleSubmit&lt;/span&gt;&lt;span class="p"&gt;((&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;))}&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Controller&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
        &lt;span class="nx"&gt;render&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{({&lt;/span&gt; &lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;error&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
          &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
            &lt;span class="p"&gt;{...&lt;/span&gt;&lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
            &lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="o"&gt;!!&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;helperText&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;?.&lt;/span&gt;&lt;span class="nx"&gt;message&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;margin&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;normal&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
            &lt;span class="nx"&gt;fullWidth&lt;/span&gt;
          &lt;span class="o"&gt;/&amp;gt;&lt;/span&gt;
        &lt;span class="p"&gt;)}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Controller&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;control&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Password is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
        &lt;span class="nx"&gt;render&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{({&lt;/span&gt; &lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;fieldState&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;error&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
          &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
            &lt;span class="p"&gt;{...&lt;/span&gt;&lt;span class="nx"&gt;field&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
            &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
            &lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="o"&gt;!!&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;helperText&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;error&lt;/span&gt;&lt;span class="p"&gt;?.&lt;/span&gt;&lt;span class="nx"&gt;message&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
            &lt;span class="nx"&gt;margin&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;normal&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
            &lt;span class="nx"&gt;fullWidth&lt;/span&gt;
          &lt;span class="o"&gt;/&amp;gt;&lt;/span&gt;
        &lt;span class="p"&gt;)}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Button&lt;/span&gt; &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;submit&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt; &lt;span class="nx"&gt;variant&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;contained&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt; &lt;span class="nx"&gt;fullWidth&lt;/span&gt; &lt;span class="nx"&gt;sx&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;mt&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
        &lt;span class="nx"&gt;Login&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/Button&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/Box&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;


&lt;p&gt;&lt;strong&gt;That's 52 lines for 2 fields.&lt;/strong&gt;&lt;/p&gt;
&lt;h3&gt;
  
  
  After (dashforge-ui)
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;DashForm&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;TextField&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Button&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;@dashforge/ui&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;type&lt;/span&gt; &lt;span class="nx"&gt;LoginForm&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="na"&gt;email&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="nl"&gt;password&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;};&lt;/span&gt;

&lt;span class="k"&gt;export&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;LoginForm&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;DashForm&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;LoginForm&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="nx"&gt;defaultValues&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;email&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;''&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;password&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;''&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="nx"&gt;onSubmit&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{(&lt;/span&gt;&lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;)}&lt;/span&gt;
    &lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Password is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Button&lt;/span&gt; &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;submit&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
        &lt;span class="nx"&gt;Login&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/Button&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/DashForm&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;


&lt;p&gt;&lt;strong&gt;That's 22 lines. 58% less code.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;No Controller.&lt;br&gt;
No manual mapping.&lt;br&gt;
No repetition.&lt;/p&gt;


&lt;h2&gt;
  
  
  Handling Real Complexity
&lt;/h2&gt;

&lt;p&gt;Because it still uses RHF under the hood, you keep all the power.&lt;/p&gt;
&lt;h3&gt;
  
  
  Conditional Fields
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;company&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Company&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;visibleWhen&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{(&lt;/span&gt;&lt;span class="nx"&gt;engine&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;accountType&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;engine&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getNode&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;accountType&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;)?.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;accountType&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;business&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;

&lt;h3&gt;
  
  
  Cross-Field Validation
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;confirmPassword&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Confirm Password&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt;
    &lt;span class="na"&gt;validate&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt;
      &lt;span class="nx"&gt;value&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;password&lt;/span&gt; &lt;span class="o"&gt;||&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Passwords do not match&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="p"&gt;}}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;

&lt;h3&gt;
  
  
  Async Validation
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt;
    &lt;span class="na"&gt;validate&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;isAvailable&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;checkEmailAvailability&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;isAvailable&lt;/span&gt; &lt;span class="p"&gt;?&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt; &lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email already registered&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="p"&gt;},&lt;/span&gt;
  &lt;span class="p"&gt;}}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;


&lt;p&gt;Same flexibility.&lt;br&gt;
Less boilerplate.&lt;/p&gt;


&lt;h2&gt;
  
  
  Performance &amp;amp; Bundle Size Impact
&lt;/h2&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;React Hook Form&lt;/strong&gt;: ~8.5kB (gzipped)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;MUI TextField + Button&lt;/strong&gt;: ~20kB (gzipped)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;dashforge-ui core&lt;/strong&gt;: ~12kB (gzipped)&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;&lt;strong&gt;Total with dashforge-ui&lt;/strong&gt;: ~40.5kB (vs ~65kB with manual RHF + MUI setup)&lt;/p&gt;

&lt;p&gt;The integration is &lt;strong&gt;actually lighter&lt;/strong&gt; because dashforge-ui eliminates the Controller overhead and consolidates common patterns.&lt;/p&gt;


&lt;h2&gt;
  
  
  Developer Experience: Before vs After
&lt;/h2&gt;

&lt;div class="table-wrapper-paragraph"&gt;&lt;table&gt;
&lt;thead&gt;
&lt;tr&gt;
&lt;th&gt;Task&lt;/th&gt;
&lt;th&gt;RHF + MUI&lt;/th&gt;
&lt;th&gt;dashforge-ui&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;tr&gt;
&lt;td&gt;Add a required text field&lt;/td&gt;
&lt;td&gt;15 lines (Controller wrapper)&lt;/td&gt;
&lt;td&gt;4 lines&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Add email validation&lt;/td&gt;
&lt;td&gt;5 lines (rules + helperText mapping)&lt;/td&gt;
&lt;td&gt;1 rule object&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Add conditional visibility&lt;/td&gt;
&lt;td&gt;~20 lines (JSX conditional)&lt;/td&gt;
&lt;td&gt;1 &lt;code&gt;visibleWhen&lt;/code&gt; function&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Type your form data&lt;/td&gt;
&lt;td&gt;Manual interface + wiring&lt;/td&gt;
&lt;td&gt;Inferred from form props&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Error handling&lt;/td&gt;
&lt;td&gt;Manual fieldState mapping&lt;/td&gt;
&lt;td&gt;Built-in, automatic&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;
&lt;td&gt;Form submission&lt;/td&gt;
&lt;td&gt;Manual handleSubmit + wiring&lt;/td&gt;
&lt;td&gt;Built-in &lt;code&gt;onSubmit&lt;/code&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/tbody&gt;
&lt;/table&gt;&lt;/div&gt;


&lt;h2&gt;
  
  
  When to Use dashforge-ui
&lt;/h2&gt;
&lt;h3&gt;
  
  
  ✅ Perfect For:
&lt;/h3&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;CRUD forms&lt;/strong&gt; (create/edit resources)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Medium to large forms&lt;/strong&gt; (8+ fields)&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Multi-step forms&lt;/strong&gt; with conditional logic&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Rapid prototyping&lt;/strong&gt; where speed matters&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Teams&lt;/strong&gt; wanting form consistency across projects&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;React + TypeScript&lt;/strong&gt; shops that value developer experience&lt;/li&gt;
&lt;/ul&gt;
&lt;h3&gt;
  
  
  ⚠️ Consider alternatives if:
&lt;/h3&gt;

&lt;ul&gt;
&lt;li&gt;You need &lt;strong&gt;completely custom field rendering&lt;/strong&gt; everywhere (dashforge-ui supports this, but with more config)&lt;/li&gt;
&lt;li&gt;Your form is a &lt;strong&gt;single-field micro-interaction&lt;/strong&gt; (vanilla RHF + MUI might be simpler)&lt;/li&gt;
&lt;li&gt;You need &lt;strong&gt;drag-and-drop form builders&lt;/strong&gt; or visual design tools&lt;/li&gt;
&lt;/ul&gt;


&lt;h2&gt;
  
  
  Why This Matters
&lt;/h2&gt;

&lt;p&gt;This is not about saving a few lines of code.&lt;/p&gt;

&lt;p&gt;It's about removing an entire category of repetitive work:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;no more Controller wrappers&lt;/li&gt;
&lt;li&gt;no more error plumbing&lt;/li&gt;
&lt;li&gt;no more field wiring&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;You focus on:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;the structure of your form&lt;/li&gt;
&lt;li&gt;the logic between fields&lt;/li&gt;
&lt;li&gt;the user experience&lt;/li&gt;
&lt;/ul&gt;


&lt;h2&gt;
  
  
  Getting Started
&lt;/h2&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight shell"&gt;&lt;code&gt;npm &lt;span class="nb"&gt;install&lt;/span&gt; @dashforge/ui @dashforge/forms @dashforge/ui-core react-hook-form @mui/material @emotion/react @emotion/styled
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;


&lt;p&gt;&lt;strong&gt;Full documentation&lt;/strong&gt;: &lt;a href="https://dashforge-ui.com" rel="noopener noreferrer"&gt;dashforge-ui.com&lt;/a&gt;&lt;/p&gt;
&lt;h3&gt;
  
  
  Minimal Example
&lt;/h3&gt;


&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;DashForm&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;TextField&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Button&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;@dashforge/ui&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="k"&gt;export&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;ContactForm&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;DashForm&lt;/span&gt;
      &lt;span class="nx"&gt;onSubmit&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{(&lt;/span&gt;&lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="nf"&gt;fetch&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;/api/contact&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
          &lt;span class="na"&gt;method&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;POST&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
          &lt;span class="na"&gt;body&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;JSON&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;stringify&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;values&lt;/span&gt;&lt;span class="p"&gt;),&lt;/span&gt;
        &lt;span class="p"&gt;});&lt;/span&gt;
      &lt;span class="p"&gt;}}&lt;/span&gt;
    &lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;name&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Name&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Name is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;email&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt;
          &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Email is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
          &lt;span class="na"&gt;pattern&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;value&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="sr"&gt;/^&lt;/span&gt;&lt;span class="se"&gt;\S&lt;/span&gt;&lt;span class="sr"&gt;+@&lt;/span&gt;&lt;span class="se"&gt;\S&lt;/span&gt;&lt;span class="sr"&gt;+$/&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;message&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Invalid email&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;},&lt;/span&gt;
        &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
        &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;message&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Message&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
        &lt;span class="nx"&gt;multiline&lt;/span&gt;
        &lt;span class="nx"&gt;rows&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="mi"&gt;4&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
        &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Message is required&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
      &lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Button&lt;/span&gt; &lt;span class="kd"&gt;type&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;submit&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
        &lt;span class="nx"&gt;Send&lt;/span&gt;
      &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/Button&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;    &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/DashForm&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;


&lt;p&gt;Fully typed. Validated. Styled with MUI. No wiring required.&lt;/p&gt;


&lt;h2&gt;
  
  
  Final Thought
&lt;/h2&gt;

&lt;p&gt;React Hook Form is great.&lt;br&gt;
Material UI is great.&lt;/p&gt;

&lt;p&gt;But the integration between them?&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;That's where most of the friction lives.&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;dashforge-ui removes that friction — by giving you components that already understand both.&lt;/p&gt;

&lt;p&gt;No layer on top. No new paradigm to learn. Just &lt;strong&gt;RHF + MUI, finally connected at the framework level.&lt;/strong&gt;&lt;/p&gt;


&lt;h2&gt;
  
  
  Beyond Simple Forms: Managing Field Dependencies
&lt;/h2&gt;

&lt;p&gt;Real-world forms have dependencies between fields.&lt;/p&gt;

&lt;p&gt;Examples:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Show a "Shipping Address" section only if the user selects "Ship to different address"&lt;/li&gt;
&lt;li&gt;Validate a "Confirm Password" field against the password value&lt;/li&gt;
&lt;li&gt;Populate a "City" dropdown based on the selected "Country"&lt;/li&gt;
&lt;li&gt;Disable a "Submit" button if dependent validations haven't passed&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;With vanilla RHF + MUI, these become spaghetti code.&lt;/p&gt;
&lt;h3&gt;
  
  
  How dashforge-ui Handles Dependencies
&lt;/h3&gt;

&lt;p&gt;Field visibility is straightforward with &lt;code&gt;visibleWhen&lt;/code&gt;:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;country&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Country&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;rules&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;required&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;
&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="cm"&gt;/* Only renders if country === 'US' */&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;TextField&lt;/span&gt;
  &lt;span class="nx"&gt;name&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;state&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;label&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;State&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
  &lt;span class="nx"&gt;visibleWhen&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{(&lt;/span&gt;&lt;span class="nx"&gt;engine&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nx"&gt;engine&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getNode&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;country&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;)?.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;US&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="sr"&gt;/&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;For more complex logic — conditional validation rules, async operations triggered by field changes, dynamic options loading — dashforge-ui uses &lt;strong&gt;Reactions&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;A Reaction is simple:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;reactions&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;
  &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;id&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;load-cities-on-country-change&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="na"&gt;watch&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;country&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;  &lt;span class="c1"&gt;// Watch for country changes&lt;/span&gt;
    &lt;span class="na"&gt;when&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nc"&gt;Boolean&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getValue&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;country&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;)),&lt;/span&gt;  &lt;span class="c1"&gt;// Only run if country has a value&lt;/span&gt;
    &lt;span class="na"&gt;run&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;country&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;getValue&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;country&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
      &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;cities&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;fetchCities&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;country&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
      &lt;span class="c1"&gt;// Update runtime state (not form values)&lt;/span&gt;
      &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;setRuntime&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;city&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;options&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;cities&lt;/span&gt; &lt;span class="p"&gt;});&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;];&lt;/span&gt;

&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;DashForm&lt;/span&gt; &lt;span class="nx"&gt;reactions&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;reactions&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
  &lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="cm"&gt;/* fields here */&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="sr"&gt;/DashForm&lt;/span&gt;&lt;span class="err"&gt;&amp;gt;
&lt;/span&gt;&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Think of Reactions as &lt;strong&gt;"When this happens, do that"&lt;/strong&gt; — they watch field changes and run side effects.&lt;/p&gt;

&lt;p&gt;This is the real power behind complex form dependencies: instead of manually wiring &lt;code&gt;useWatch&lt;/code&gt; + &lt;code&gt;useEffect&lt;/code&gt; chains, you describe &lt;strong&gt;what triggers what&lt;/strong&gt; at the form level.&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Want to go deeper?&lt;/strong&gt; I've written a detailed guide on this exact problem:&lt;/p&gt;

&lt;p&gt;📖 &lt;strong&gt;&lt;a href="https://dev.to/kensaadi/building-dependent-form-fields-in-react-a-practical-approach-3il2"&gt;Building Dependent Form Fields in React: A Practical Approach&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;That guide covers dependency patterns, performance implications, and real-world solutions. dashforge-ui integrates those patterns into the component model.&lt;/p&gt;




&lt;p&gt;&lt;strong&gt;👉 If you're using React Hook Form today, I'm curious: how much of your form code is actual logic vs wiring?&lt;/strong&gt;&lt;/p&gt;

&lt;p&gt;&lt;strong&gt;Learn more&lt;/strong&gt;: &lt;a href="https://dashforge-ui.com" rel="noopener noreferrer"&gt;dashforge-ui.com&lt;/a&gt;&lt;br&gt;&lt;br&gt;
&lt;strong&gt;GitHub&lt;/strong&gt;: &lt;a href="https://github.com/dashforge-ui" rel="noopener noreferrer"&gt;github.com/dashforge-ui&lt;/a&gt;&lt;br&gt;&lt;br&gt;
&lt;strong&gt;Deep dive on dependencies&lt;/strong&gt;: &lt;a href="https://dev.to/kensaadi/building-dependent-form-fields-in-react-a-practical-approach-3il2"&gt;Building Dependent Form Fields in React&lt;/a&gt;&lt;/p&gt;

</description>
      <category>rhf</category>
      <category>mui</category>
      <category>react</category>
      <category>dashforge</category>
    </item>
    <item>
      <title>Building Dependent Form Fields in React: A Practical Approach</title>
      <dc:creator>kensaadi</dc:creator>
      <pubDate>Mon, 27 Apr 2026 15:57:12 +0000</pubDate>
      <link>https://dev.to/kensaadi/building-dependent-form-fields-in-react-a-practical-approach-3il2</link>
      <guid>https://dev.to/kensaadi/building-dependent-form-fields-in-react-a-practical-approach-3il2</guid>
      <description>&lt;p&gt;Have you ever needed a form where changing one field updates the options of another? Like selecting a category and seeing subcategories automatically update?&lt;/p&gt;

&lt;p&gt;Most developers reach for &lt;code&gt;useEffect&lt;/code&gt; + manual state management. But there's a better way.&lt;/p&gt;

&lt;h2&gt;
  
  
  The Problem
&lt;/h2&gt;

&lt;p&gt;Let's say you have two autocomplete fields:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Category&lt;/strong&gt; - static options&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Subcategory&lt;/strong&gt; - depends on category, loads dynamically&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;The traditional approach requires:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Tracking category changes&lt;/li&gt;
&lt;li&gt;Triggering updates when category changes&lt;/li&gt;
&lt;li&gt;Manual state management for loading/error states&lt;/li&gt;
&lt;li&gt;Clearing subcategory when category changes&lt;/li&gt;
&lt;li&gt;Managing async operations&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;It gets complex fast when you add more dependencies.&lt;/p&gt;

&lt;h2&gt;
  
  
  The DashForge Solution
&lt;/h2&gt;

&lt;p&gt;DashForge uses &lt;strong&gt;reactions&lt;/strong&gt; - a declarative way to handle field dependencies:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;useState&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;react&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;DashForm&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;@dashforge/forms&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;Autocomplete&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;@dashforge/ui&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="k"&gt;import&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;Box&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Button&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Card&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Stack&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;Typography&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;from&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;@mui/material&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kr"&gt;interface&lt;/span&gt; &lt;span class="nx"&gt;FormValues&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nl"&gt;category&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;string&lt;/span&gt; &lt;span class="o"&gt;|&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="nl"&gt;subcategory&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;string&lt;/span&gt; &lt;span class="o"&gt;|&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;categories&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Electronics&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Clothing&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Books&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;];&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;subcategoriesByCategory&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;Record&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="na"&gt;Electronics&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Phones&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Laptops&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Tablets&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Accessories&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
  &lt;span class="na"&gt;Clothing&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Shirt&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Pants&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Shoes&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Dresses&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
  &lt;span class="na"&gt;Books&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Fiction&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Non-Fiction&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Science&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;History&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
&lt;span class="p"&gt;};&lt;/span&gt;

&lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;fetchSubcategories&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;category&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;string&lt;/span&gt; &lt;span class="o"&gt;|&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;Promise&lt;/span&gt;&lt;span class="p"&gt;((&lt;/span&gt;&lt;span class="nx"&gt;resolve&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="nf"&gt;setTimeout&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;resolve&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;500&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt;
  &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;category&lt;/span&gt; &lt;span class="p"&gt;?&lt;/span&gt; &lt;span class="nx"&gt;subcategoriesByCategory&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;category&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;||&lt;/span&gt; &lt;span class="p"&gt;[]&lt;/span&gt; &lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[];&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="k"&gt;export&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;DependencyForm&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setFormData&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;useState&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;onSubmit&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;FormValues&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;setFormData&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;data&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;};&lt;/span&gt;

  &lt;span class="k"&gt;return &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
        &lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;DashForm&lt;/span&gt;
          &lt;span class="nx"&gt;onSubmit&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;onSubmit&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;
          &lt;span class="nx"&gt;defaultValues&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{{&lt;/span&gt; &lt;span class="na"&gt;category&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="na"&gt;subcategory&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt; &lt;span class="p"&gt;}}&lt;/span&gt;
          &lt;span class="nx"&gt;reactions&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{[&lt;/span&gt;
            &lt;span class="p"&gt;{&lt;/span&gt;
              &lt;span class="na"&gt;id&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;update-subcategory-options&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
              &lt;span class="na"&gt;watch&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;category&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
              &lt;span class="na"&gt;run&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;getValue&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setRuntime&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
                &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;category&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;getValue&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;category&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

                &lt;span class="nf"&gt;setRuntime&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;subcategory&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
                  &lt;span class="na"&gt;status&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;loading&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
                  &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
                  &lt;span class="na"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;options&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[]&lt;/span&gt; &lt;span class="p"&gt;},&lt;/span&gt;
                &lt;span class="p"&gt;});&lt;/span&gt;

                &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;subcategories&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nf"&gt;fetchSubcategories&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;category&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

                &lt;span class="nf"&gt;setRuntime&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;subcategory&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
                  &lt;span class="na"&gt;status&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;ready&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
                  &lt;span class="na"&gt;error&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
                  &lt;span class="na"&gt;data&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="na"&gt;options&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;subcategories&lt;/span&gt; &lt;span class="p"&gt;},&lt;/span&gt;
                &lt;span class="p"&gt;});&lt;/span&gt;
              &lt;span class="p"&gt;},&lt;/span&gt;
            &lt;span class="p"&gt;},&lt;/span&gt;
          &lt;span class="p"&gt;]}&lt;/span&gt;
        &lt;span class="o"&gt;&amp;gt;&lt;/span&gt;
            &lt;span class="nx"&gt;Submit&lt;/span&gt;
        &lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt; &lt;span class="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;
            &lt;span class="p"&gt;{&lt;/span&gt;&lt;span class="nx"&gt;JSON&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;stringify&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;formData&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="kc"&gt;null&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;)}&lt;/span&gt;
        &lt;span class="p"&gt;)}&lt;/span&gt;
  &lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h2&gt;
  
  
  How It Works
&lt;/h2&gt;

&lt;p&gt;&lt;strong&gt;The key is the &lt;code&gt;reactions&lt;/code&gt; array:&lt;/strong&gt;&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;
&lt;strong&gt;watch&lt;/strong&gt; - Specify which fields to monitor&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;run&lt;/strong&gt; - When watched fields change, execute this function&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;getValue&lt;/strong&gt; - Read current field values from the form&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;setRuntime&lt;/strong&gt; - Update field data at runtime (options, loading state, errors)&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;When category changes:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Reaction triggers automatically&lt;/li&gt;
&lt;li&gt;Fetch new subcategories&lt;/li&gt;
&lt;li&gt;Update subcategory field with new options&lt;/li&gt;
&lt;li&gt;User sees updated options immediately&lt;/li&gt;
&lt;/ol&gt;

&lt;h2&gt;
  
  
  Why This Approach is Better
&lt;/h2&gt;

&lt;h3&gt;
  
  
  No Manual Side Effects
&lt;/h3&gt;

&lt;p&gt;The form handles dependencies automatically. No need for &lt;code&gt;useEffect&lt;/code&gt; or manual state management.&lt;/p&gt;

&lt;h3&gt;
  
  
  Clean Dependencies
&lt;/h3&gt;

&lt;p&gt;Just declare what you're watching with the &lt;code&gt;watch&lt;/code&gt; array. No complex dependency tracking.&lt;/p&gt;

&lt;h3&gt;
  
  
  Loading States Built-in
&lt;/h3&gt;

&lt;p&gt;Set &lt;code&gt;status: "loading"&lt;/code&gt; and the field knows it's fetching. Built-in support for async operations.&lt;/p&gt;

&lt;h3&gt;
  
  
  Type-Safe
&lt;/h3&gt;

&lt;p&gt;Full TypeScript support for &lt;code&gt;getValue&lt;/code&gt; and &lt;code&gt;setRuntime&lt;/code&gt;.&lt;/p&gt;

&lt;h3&gt;
  
  
  Scales Well
&lt;/h3&gt;

&lt;p&gt;Add another dependent field? Add another reaction. Complexity stays linear, not exponential.&lt;/p&gt;

&lt;h2&gt;
  
  
  Advanced: Multiple Dependencies
&lt;/h2&gt;

&lt;p&gt;What if subcategory affects another field? Just add another reaction:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="nx"&gt;reactions&lt;/span&gt;&lt;span class="o"&gt;=&lt;/span&gt;&lt;span class="p"&gt;{[&lt;/span&gt;
  &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;id&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;update-subcategory-options&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="na"&gt;watch&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;category&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
    &lt;span class="na"&gt;run&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;getValue&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setRuntime&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="c1"&gt;// Update subcategory based on category&lt;/span&gt;
    &lt;span class="p"&gt;},&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt;
  &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;id&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;update-product-options&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="na"&gt;watch&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;subcategory&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt;
    &lt;span class="na"&gt;run&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;async &lt;/span&gt;&lt;span class="p"&gt;({&lt;/span&gt; &lt;span class="nx"&gt;getValue&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;setRuntime&lt;/span&gt; &lt;span class="p"&gt;})&lt;/span&gt; &lt;span class="o"&gt;=&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="c1"&gt;// Update product based on subcategory&lt;/span&gt;
    &lt;span class="p"&gt;},&lt;/span&gt;
  &lt;span class="p"&gt;},&lt;/span&gt;
&lt;span class="p"&gt;]}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The form orchestrates the entire dependency chain.&lt;/p&gt;

&lt;h2&gt;
  
  
  Real-World Scenarios
&lt;/h2&gt;

&lt;p&gt;This pattern works for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Cascading dropdowns&lt;/strong&gt; - Country → State → City&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Dynamic pricing&lt;/strong&gt; - Product → Variant → Price&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Conditional visibility&lt;/strong&gt; - Type → Related options&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Async data loading&lt;/strong&gt; - Search field → fetch results&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Complex workflows&lt;/strong&gt; - Multi-step forms with dependencies&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Getting Started
&lt;/h2&gt;

&lt;p&gt;Install DashForge:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight shell"&gt;&lt;code&gt;npm &lt;span class="nb"&gt;install&lt;/span&gt; @dashforge/forms @dashforge/ui
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;See the &lt;a href="https://dashforge-ui.com/docs" rel="noopener noreferrer"&gt;full documentation&lt;/a&gt; for API details.&lt;/p&gt;

&lt;p&gt;Check out the &lt;a href="https://dashforge-ui.com/starter-kits" rel="noopener noreferrer"&gt;starter kits&lt;/a&gt; for production examples.&lt;/p&gt;

&lt;h2&gt;
  
  
  The Point
&lt;/h2&gt;

&lt;p&gt;Dependent form fields don't need to be complex. With the right abstraction, they become straightforward: declare what you're watching, declare what updates, let the form handle the rest&lt;/p&gt;

&lt;p&gt;Check video &lt;a href="https://youtu.be/aQullHAiX0c?si=5K5FDVv2V_GUl5vv" rel="noopener noreferrer"&gt;Youtube - &lt;br&gt;
React forms get messy fast — especially with dependent fields&lt;/a&gt;&lt;/p&gt;

</description>
      <category>react</category>
      <category>forms</category>
      <category>typescript</category>
      <category>dashforge</category>
    </item>
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