The success of my last blog has cursed me with the burden of EXPECTATIONS. I've accidentally set the bar too high and now have to pretend I'm good at this. To cope with this crushing pressure, I’ve turned to the most emotionally stable things in my life:
- Wine
- Hallmark Christmas movies where small towns have better WiFi than my house.
[Originally drafted in December. Finally committed in January. Yes - Procrastination is my brand. 😌]
Four movies deep into "Career-oriented big City Girl falls for handsome small town tree farmer who saves her from personal or professional ruin", I remember: oh right - I have a React blog to write.
And then I thought: God, I wish React were more like the ruggedly handsome Christmas-tree-farm guy with the flannel shirt and the jawline. sigh
Steady. Predictable. Doesn't have a meltdown because someone three counties over changed their order about pie flavors.
Also — and I cannot stress this enough — devastatingly handsome.
React's whole brand is "I’m the stable, predictable framework. I make UI updates easy.”
LIES! ABSOLUTE LIES I SAY!
He will re-render because his cousin’s, ex-girlfriend’s props changed even though he hasn’t spoken to that cousin since Thanksgiving ’09 or - just because you made eye contact.
React whispers sweet nothings like "I'm just a library standing in front of a dev, asking her to love me" and then casually mentions you'll need React Router, React Query, React Hook Form, and 47 other "react-something" packages - not his problem.
So in the spirit of holiday romance — and my heart's desire to understand his backstory, I present to you:
From CDN to Pixel: A React App’s Journey from "npm run build" to "oh look, a button"
The Browser (let's call her... Browser) arrives in town, confident and capable. She's been rendering content since 1995. She's parsed HTML that would make you weep. She's survived the IE6 era. She's seen some stuff.
She can handle anything.
Then she meets React.
And So it Begins...
Browser types www.small-town-love-story.com and hits Enter.
DNS resolves to Netlify's CDN. Geography decides the rest - Dallas browser hits Dallas edge, London hits London. Same IP, different physical server (Anycast routing).
Encrypted connection established.
This is the Hallmark prelude - the editor ultimatum, the rushed flight home, the "I'm only here for the holidays" trope.
CDN edge responds with cached index.html
Browser Meets index.html
She makes her first friend in town. Naturally, she owns the only café that exists in this town.
It's empty right now.
Mostly just a <div id="root"></div> but it's got potential...
"I'm a container." index.html says cheerfully. "Once React gets here, this place is gonna be bustling!"
"We need to save the town Christmas party." she tells Browser. Of course. Duh! The obligatory catastrophe.
React is still en route from the CDN - packed in those JavaScript files, probably bringing his entire component tree as carry-on.
Winter is coming...
React Finally Shows Up
Cue the slow-motion entrance.
Hair blowing in non-existent wind. Flannel shirt unbuttoned just enough.
And the abs.
The glorious abs.
Browser's JavaScript engine parses ~170KB of bundles.
Parse time: ~80-100ms.
Single-threaded.
Blocking.
This is why bundle size matters - not download time (CDNs are fast), but parse time. Every kilobyte is CPU work grinding away on the main thread while nothing else can happen.
He spots that empty <div id="root"></div>.
"I'll take it from here," he announces, rolling up his sleeves.
Browser, who's been busy with DNS resolution, TLS handshakes, HTML parsing, and resource orchestration - of course feels the unmistakable pull toward the ruggedly handsome protagonist with the heart of gold.
Don't roll your eyes people! It is a rom-com! What else did you expect?
The Town Shows Up (Or: How the Christmas Party Actually Gets Saved)
So, now to avert the impending apocalypse, our protagonist React rallies the super-friendly townsfolk.
He's got the vision. The coordination. The jawline.
But it takes the whole town to actually make it happen.
JavaScript Engine shows up first — runs React’s code, schedules tasks, queues microtasks, and keeps the main thread alive.
Rendering Engine does the real construction — creates actual DOM nodes (C++ objects in memory), parses CSS, assembles the render tree by combining DOM + CSSOM.
Layout Engine measures everything — exact sizes, positions, box model math, flexbox negotiations, grid calculations. Nothing is guessed. This is reflow and it's expensive.
Paint rasterizes to pixels. Until this moment, nothing was visible. Just data structures.
Compositor breaks the page into layers, hands them to the GPU — transforms, opacity, z-index. Aims for 60fps.
The OS, our mayor, gives the final blessings — input events, thread scheduling, screen refresh.
Pixels hit the screen.
The title "Once Upon a Holiday" fades in.
Okay, she thinks. Maybe he's not completely useless.
The abs certainly don't hurt.
The First Tiff: React's Re-render Philosophy
It’s been a few days.
The title looks cute in its cursive font.
The town has settled. Our couple has routines.
Then a user clicks a button.
State changes.
React panics.
He re-renders everything.
"The counter went from 0 to 1," Browser says, very calmly. "Why are you calling every component function again?"
"Re-renders are cheap. It's just JavaScript," React shrugs.
"I have to recalculate layout. Repaint pixels. Composite layers." Browser's voice tightens. "You just re-rendered 47 components to change one text node."
"Declarative updates," React says defensively. "Simple. Predictable."
"Simple for you. I'm doing the actual work."
React looks away. She's mad.
This is The Big Fight™.
(Hallmark fights, am I right? 🙄 In production this wouldn’t even log a warning.)
Browser Packs Her Bags
A few days later, Browser is at the train station, suitcase packed.
"I have other apps to render," she tells index.html. "Other frameworks to work with. This was... temporary"
React shows up breathless. Hair still perfect - obviously.
"Wait!"
Browser turns. "What now? Did you bring your 47 npm packages to say goodbye?"
"I've been working on something," React says. "Memoization."
Browser blinks.
"React.memo. useMemo. useCallback." He's talking fast. "I can skip re-renders now. Only update what actually changed. Like you kept telling me to do."
"And there's more!" React continues. "React Compiler. Automatic memoization. I don't even have to think about optimization anymore. It just... happens."
She likes this.
"Sixty frames per second?" she asks.
"Sixty," React promises. "Even under pressure."
Browser sets the suitcase down.
They kiss.
Before you gag — a reminder:
it is a rom-com.
6 Months Later
React didn’t become perfect.
Browser didn’t stop doing all the work.
But now they understand each other.
Snow falls softly over the town.
Fade to black.
(Post-credits scene: someone forgets a dependency array.)
Top comments (8)
This was genuinely fun to read and surprisingly clear at the same time — the storytelling made a complex render pipeline feel intuitive instead of intimidating. I really like how you balanced humor with real performance insights, especially around parse time and re-renders. It made me rethink how casually I treat “cheap” updates in React. Looking forward to more posts like this, especially if you keep blending deep technical takes with this kind of narrative style.
Thank you! And yes, explaining technical concepts through humorous metaphors is very much my thing right now 😄
If you’re into that style, a few others you might enjoy:
"React in its Sigma Era" (React 19.2 updates)
"Ceramic Life Coach" (job searching)
"React and the City ⚔️ Part 3: Return of the MCP" (LLM/MCP app)
and a few others...
Really glad you enjoyed the read - thanks again!
It's very impressive.
Good luck!
Thank you! I appreciate it!
Great blog Anju!!!!
Thank you, my dear Mariya!!! 🥰
Wow Anju great blog, as always!
Sofia! Thank you so much! 🩵