Amit Maurya

Posted on Mar 18

I gave AI my React codebase - here's how it made me 3x faster (Cursor AI honest review)

#react #ai #cursor #javascript

Not a sponsored post. No fluff. Just a senior dev's real experience after 3 months of daily use.

I have been writing JavaScript/React/Nextjs for 10 years.

I have survived jQuery to React migrations, Redux boilerplate hell, the hooks revolution, and every "React is dead" kind of tweet.

So when everyone started screaming about AI coding tools, I was like BEHIND.

I would tried GitHub Copilot. It was fine. Autocomplete on steroids. Cool, but not life-changing game.

Then I tried Cursor AI on my actual production React codebase on large-scale platform with multiple repos, a shared component of repo and a Next.js as a frontend.

Three months later? I genuinely cannot imagine going back.

Here's my brutally honest review - what works, what does not, and exactly how I use it daily.

🤔 What Even Is Cursor AI?

Cursor is a VS Code fork with AI baked deep into the editor - not bolted on as a plugin in the system.

The difference matters. With Copilot, AI is a suggestion engine. With Cursor, AI is a collaborator that and feels like pair programming.

Understands your entire codebase, not just the file you are in
Can edit multiple files at once based on one instruction give to it
Answers questions about your own code ("why is this component re-rendering again?")
Fixes bugs by reading your error + your code together at once.

Think of it as the difference between a calculator and a junior developer who has read every file in your repo.

⚙️ My Setup (Multi-Repo React Project)

My codebase structure:

/react-frontend          ← Main consumer app
/shared-component        ← Shared component library
/nextjs-frontend       ← Next.js as a dashboard

Three repos. Shared dependencies. Complex component tree.

This is exactly where most AI tools fail - they get confused across repos and lose context.

Here's my .cursorrules file that solved this:

You are an expert React and Next.js developer.
This project uses TypeScript, Redux Toolkit, Tailwind CSS.
Shared components live in /shared-component  always import from there.
Never use inline styles. Always use Tailwind utility classes.
State management: Redux for global, useState for local UI state only.
When creating components, always add PropTypes or TypeScript interfaces.
Follow atomic design: atoms → molecules → organisms → pages.

This single file made Cursor 10x more accurate for my specific codebase. Game changer.

🚀 The 5 Things That Actually Made Me 3x Faster

1. `Ctrl+K` — Edit Code With a Single Instruction

Select any block of code → Ctrl+K → type what you want.

Real example from my project:

I had this messy component:

// Before — 47 lines of manual className logic
const Button = ({ variant, size, disabled, loading, children }) => {
  let className = 'btn';
  if (variant === 'primary') className += ' btn-primary';
  if (variant === 'secondary') className += ' btn-secondary';
  if (size === 'sm') className += ' btn-sm';
  if (size === 'lg') className += ' btn-lg';
  if (disabled) className += ' btn-disabled';
  if (loading) className += ' btn-loading';
  // ... 40 more lines
}

I selected it, hit Ctrl+K, typed:

"Refactor this to use Tailwind CVA (class-variance-authority) with TypeScript"

In 8 seconds I got:

// After — clean, typed, scalable
import { cva, type VariantProps } from 'class-variance-authority';

const buttonVariants = cva(
  'inline-flex items-center justify-center rounded-md font-medium transition-colors',
  {
    variants: {
      variant: {
        primary: 'bg-blue-600 text-white hover:bg-blue-700',
        secondary: 'bg-gray-100 text-gray-900 hover:bg-gray-200',
      },
      size: {
        sm: 'h-8 px-3 text-sm',
        md: 'h-10 px-4',
        lg: 'h-12 px-6 text-lg',
      },
    },
    defaultVariants: { variant: 'primary', size: 'md' },
  }
);

interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {
  loading?: boolean;
}

const Button = ({ variant, size, loading, children, ...props }: ButtonProps) => (
  <button className={buttonVariants({ variant, size })} {...props}>
    {loading ? <Spinner /> : children}
  </button>
);

What would havve taken me 45 minutes took 8 seconds. That's the 3x.

2. `Ctrl+L` — Chat With Your Codebase

This is where Cursor separates itself from everything else.

I can ask:

"Why is the UserDashboard component re-rendering on every route change?"

And Cursor reads my actual files, traces the Redux selectors, finds the missing useMemo, and explains it - with the exact line to fix at any time.

No copying code into ChatGPT or deepsheek, claude code. No context switching. It knows my code.

Another real example - I asked:

"Find all places in the codebase where we are doing direct API calls instead of using our apiService utility"

It scanned all 400+ files and returned a list with file paths and line numbers.

A task that would take me 2 hours of grep took 30 seconds.

3. Multi-File Edits - The Real Power Move

This is the feature that genuinely shocked me and will you as well

I typed:

"Add a new 'isVerified' prop to the UserCard component, update its TypeScript interface, update all usages across the codebase, and add it to the Storybook story"

Cursor opened 6 files simultaneously, made coordinated edits across all of them, and showed me a diff to review.

Previously this was a 2-hour task involving grep, find-replace, and manually checking every usage. Now it's a 5-minute review of AI-generated changes.

4. Bug Fixing - Paste Error, Get Fix

My previous workflow when hitting an error:

Read error
Google it
Open Stack Overflow
Read 3 answers
Try one
Fail
Repeat

My current workflow:

Ctrl+L
Paste error
Read the fix
Apply it

Real example - I was getting this cryptic error:

Warning: Can't perform a React state update on an unmounted component.
This is a no-op, but it indicates a memory leak in your application.

I pasted it into Cursor chat with zero other context. It:

Identified which async call was causing it
Explained why it happens
Gave me the useEffect cleanup function fix
Warned me about 2 other places in my code with the same pattern

No Googling. No Stack Overflow. Done.

5. Writing Tests - From Dread to Done

I wiill be honest here. I used to avoid writing tests because they took so long.

Now I select a component, hit Ctrl+K, type:

"Write comprehensive React Testing Library tests for this component covering all variants and edge cases"

And I get 80% complete test coverage in seconds. I review, tweak, done.

My test coverage went from ~20% to ~65% in one month. Not because I got more disciplined — because it stopped being painful.

❌ What Cursor Gets WRONG (Honest Part)

It is not perfect. Here's where it struggles:

1. Large Context = Confused Output
If you dump 5 huge files into context and ask a complex question, the output quality drops. I learned to keep prompts focused and specific.

2. It Can Confidently Generate Wrong Code
The output always looks right. Sometimes it's subtly wrong. Never skip code review. You are still the engineer. Alwasy remember

3. It Does not Know Your Business Logic
It knows React. It does not know why your app works the way it does. The .cursorrules file helps, but domain context still needs to come from you.

4. Subscription Cost
Cursor Pro is $20/month. If you are on a tight budget, evaluate it against actual time saved. For me, it's a no-brainer ROI.

📊 My Honest Numbers After 3 Months

Task	Before Cursor	After Cursor
New component (with types + tests)	~2 hours	~35 mins
Bug fix (unknown root cause)	~1.5 hours	~25 mins
Refactor existing component	~1 hour	~15 mins
Code review prep	~45 mins	~15 mins
Writing unit tests	~2 hours	~30 mins

Is it exactly 3x? On some days yes. On others maybe 2x. and somedays no. But consistently faster, every single day — that's the real win.

🛠️ My Starter `.cursorrules` Template (Copy This)

You are an expert [React/Vue/Angular] developer.
Tech stack: [list your stack]
Styling: [Tailwind/CSS Modules/Styled Components]
State: [Redux/Zustand/Context]
Testing: [Jest/Vitest + Testing Library]

Rules:
- Always write TypeScript with strict types
- No any types unless absolutely necessary
- Components must be under 150 lines - suggest splitting if larger
- Always handle loading and error states
- Write accessible HTML (ARIA labels, semantic elements)
- Add JSDoc comments for all exported functions

Customize it for your project and drop it in your repo root. Your AI suggestions will become dramatically more accurate.

🤔 Should YOU Try Cursor?

Yes, if you:

Write React/Next.js professionally
Work on codebases with 10k+ lines
Want to ship features faster without sacrificing quality
Are curious about AI-assisted development

Maybe wait, if you:

Are still learning fundamentals - don't let AI become a crutch
Work on a tiny solo project where the overhead isn't worth it

Final Take

I'm a 10-year Frontend Architect veteran. I don't hype tools easily.

But Cursor changed how I work. Not because it replaces my thinking - it amplifies it.

The best analogy: imagine having a junior dev who has read every file in your codebase, never gets tired, never judges your questions, and responds in 3 seconds. That's Cursor.

The devs who learn to work with AI tools right now are going to have a serious edge over those who don't. I've seen it in my own output.

If this helped you, drop a ❤️ and follow me - I write about AI tools for React/Next.js developers whenever gets time.

Want to go deeper on AI-powered frontend development? I offer 1:1 mentoring sessions where we work through your actual codebase together.
📅 Book a session → topmate.io/amitaicraft

APPLY COUPON FIRST100 and get FLAT 20% discount on your booking.

lets connect.