React DevTools — React Technical Interview Questions & Answers

React DevTools

React DevTools

  • React Developer Tools (browser extension) shows the component tree, props, hooks state, and a profiler for why something re-rendered. Faster than sprinkling console.log. Components tab for values, Profiler for performance.
  • React DevTools — output: three uses. Faster than console.log on every render.

Technical Interview Tip: Two tabs: Components + Profiler.

Code Examples for React DevTools

Example

// DevTools
console.log("install React Developer Tools");
console.log("Components tab → pick Hello → see props/hooks");
console.log("Profiler → what re-rendered");

React DevTools — output: three uses. Faster than console.log on every render.

How to Explain React DevTools to an Interviewer

Explain React DevTools as if you are teaching a junior — definition, then one tiny UI.

Components : props + hooks. Profiler : re-renders.

What does the example show on screen (or print), and what does that prove?

React DevTools — output: three uses

What mistake do freshers make with React DevTools?

localhost too.