Q121. Why is normalized state important for performance?
1. **O(1) lookups by ID** instead of scanning/`find()`-ing through an array every time a component needs one item. 2. **Updates are localized**: changing one entity only ...
Technical Question Bank · Peer-Reviewed
Job Interview Questions and Answers Directory
Search and filter frequently asked interview questions across technical, programming, and behavioral domains. Tailor your interview preparation by difficulty for freshers or experienced developers (138 available).
Active:
Tag: components ×
Q122. How do you debug a Redux performance problem?
A practical, step-by-step approach: 1. **Confirm it's actually Redux**: use the React DevTools **Profiler** to see which components re-render and how often, before assumi...
Q123. What is the difference between BrowserRouter, HashRouter, and MemoryRouter?
All three are drop-in `` implementations from `react-router-dom` (see [What are the `` components of React Router v6?](#what-are-the-router-components-of-react-router-v6)...
Q124. What are loaders, actions, and data APIs in modern React Router?
Starting with React Router v6.4, the library ships **data APIs** (`createBrowserRouter`, `loader`, `action`, `useLoaderData`, `useActionData`, `useFetcher`) that move dat...
Q125. How to bind methods or event handlers in JSX callbacks?
There are 3 possible ways to achieve this in class components: 1. **Binding in Constructor:** In JavaScript classes, the methods are not bound by default. The same rule a...
Q126. What are forward refs?
_Ref forwarding_ is a feature that lets some components take a _ref_ they receive, and pass it further down to a child. ```jsx harmony const ButtonElement = React.forward...
Q127. What is context?
_Context_ provides a way to pass data through the component tree without having to pass props down manually at every level. For example, authenticated users, locale prefe...
Q128. What are error boundaries in React v16?
**Note:** Error boundaries were introduced in React 16 and remain valid in current React versions (18/19). _Error boundaries_ are components that catch JavaScript errors ...
Q129. How you use decorators in React?
You can _decorate_ your _class_ components, which is the same as passing the component into a function. **Decorators** are flexible and readable way of modifying componen...
Q130. What is the recommended way for naming components?
It is recommended to name the component by reference instead of using `displayName`. Using `displayName` for naming component: ```javascript export default React.createCl...