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Hoài Nhớ ( Nick )
Hoài Nhớ ( Nick )

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React Debugger Extension: Detect Re-renders, Memory Leaks, and Anti-patterns in Real Time

#react #extensions #webdev #productivity

Stop Debugging React Blindly: Meet React Debugger Extension

A powerful Chrome DevTools extension that makes debugging React applications feel less like guesswork and more like detective work.

The Problem Every React Developer Faces

We've all been there. Your React app is slow. Components re-render for no apparent reason. Memory usage keeps climbing. Layout shifts ruin the user experience. And you're left wondering: where do I even start?

Traditional debugging tools help, but they weren't built with React's unique challenges in mind. That's why I built React Debugger Extension — a Chrome DevTools extension specifically designed to surface the issues that matter most in React applications.

What Makes This Different?

Unlike generic performance tools, React Debugger understands React's mental model. It hooks directly into React's fiber architecture to give you insights that are actually actionable.

UI & State Issues Detection

Catch anti-patterns before they become bugs:

  • Direct state mutation — The silent killer of React apps
  • Missing keys — That console warning you've been ignoring
  • Index as key — Works until it spectacularly doesn't
  • Duplicate keys — When your list goes haywire

Performance Analysis

See exactly what's slowing you down:

  • Component render statistics with timing data
  • Top re-rendering components — Find the culprits instantly
  • Render triggers (props, state, context, parent) — Know why it rendered
  • React Scan visualization — See re-renders directly on the page with color-coded overlays

Side Effects Monitoring

useEffect issues are notoriously hard to debug. Not anymore:

  • Missing cleanup detection
  • Dependency array problems
  • Infinite loop risks
  • Stale closure warnings

CLS (Cumulative Layout Shift) Tracking

Layout shifts destroy UX. Track them in real-time:

  • Live CLS score monitoring
  • Top shift contributors identified by element
  • Timeline of shift events

Redux DevTools Built-In

No need for separate extensions:

  • State tree browser with search
  • Action history
  • Dispatch custom actions for testing

Memory Monitoring

Catch memory leaks before your users do:

  • Heap usage tracking
  • Growth rate analysis
  • Crash log with stack traces

Timeline View

See everything in chronological order:

  • Renders, state changes, effects, errors — all correlated
  • Filter by event type
  • Search for specific components
  • Capture snapshots for comparison

Installation

Option 1: One Command (Recommended) 

npx @nhonh/react-debugger
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Then load it in Chrome:

  1. Go to chrome://extensions/
  2. Enable Developer mode
  3. Click Load unpacked
  4. Select the downloaded folder

That's it. Open DevTools (F12) and find the "React Debugger" tab.

Option 2: From Source 

git clone https://github.com/hoainho/react-debugger-extension.git
cd react-debugger-extension
npm install
npm run build
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Load the dist folder in Chrome as above.

See It In Action

Catching Index-as-Key Issues 

// This common mistake gets flagged immediately
{items.map((item, index) => (
  <li key={index}>{item}</li>
))}
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Open the UI & State tab, see the warning, and fix it before it causes bugs.

Finding Excessive Re-renders

Enable React Scan in the Performance tab. Components flash with colors:

  • Green = 1 render (good)
  • Yellow = 2-3 renders (watch it)
  • Red = 10+ renders (investigate now)

Detecting Missing Cleanup 

useEffect(() => {
  const id = setInterval(() => console.log("tick"), 1000);
  // Missing cleanup = memory leak
}, []);
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The Side Effects tab catches this instantly and tells you exactly what's wrong.

Built for Developers at Every Level

Juniors

Start with the UI & State and Side Effects tabs. Learn React patterns by seeing what NOT to do — with actionable suggestions for every issue.

Mid-Level

Focus on the Performance and Timeline tabs. Understand render cascades. Apply React.memo, useMemo, useCallback where they actually matter.

Seniors

Use all tabs for a holistic view. Correlate Redux actions with render storms. Monitor memory patterns over time. Optimize CLS for better Core Web Vitals scores.

Why I Built This

After years of debugging React applications, I got tired of the same cycle:

  1. User reports slowness
  2. Open React DevTools Profiler
  3. Stare at flame graphs
  4. Make educated guesses
  5. Repeat until something works

React Debugger cuts through the noise. It tells you:

  • What is wrong
  • Where it's happening
  • Why it's a problem
  • How to fix it

Links

Open Source & MIT Licensed

This is a community tool. Contributions are welcome — whether it's bug reports, feature requests, or pull requests.

Give it a try. Break your bad React habits. Ship faster, more reliable applications.

Your React apps deserve better debugging.

Built by NhoNH

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