Top 60+ React Interview Questions and Answers – 2025….Coding exercise questions are coming soon!! You will get latest React Interview Questions & Answers.
What is React?
An open-source front-end JavaScript package called React (also known as React.js or ReactJS) is used to create reusable user interfaces, particularly for single-page apps. It is used to handle the view layer for declaratively driven online and mobile applications.
What is React?
The major features of React Js are:
- React Js uses JSX syntax which help users to write html syntax in the javascript code.
- Another major feature of react js is it uses virtual dom concept . React Js Do not use real dom which makes react js faster than other frontend stacks.
- For optimization and SEO purposes, it uses server-sidever side rendering.
- By using react js developers can make reusable components and reuse the code on different places .
What is JSX ?
JavaScript XML, or JSX, is an extension of ECMAScript that has syntax similar to XML.In the example below, the text inside <h1> tag is returned as JavaScript function to the render function.
What is the difference b/w CRA and vite ?
| CRA | Vite | |
|---|---|---|
| Uses Webpack, which can be slow, especially in large projects. | Uses ESBuild for fast bundling and native ESM (ES Modules) for instant hot reloads, making it significantly faster. | |
| Slow startup time due to Webpack bundling everything before the dev server starts. | Instant dev server startup by only processing files when they are requested. | |
| Slower build process due to Webpack’s bundling method. | Faster builds due to ESBuild, which is optimized for speed. | |
| HMR can be slow, especially for large apps. | Faster HMR because it uses ESM, meaning only changed modules are updated. | |
| Comes with a lot of pre-configured settings but can be difficult to customize unless you eject. | Easier customization with its plugin-based architecture. | |
| May generate larger builds due to Webpack’s bundling strategy. | Smaller and more optimized builds due to ESBuild and Tree Shaking. |
What is state in React?
State of a component is an object that holds some information that may change over the lifetime of the component. The important point is whenever the state object changes, the component re-renders.
- Lets take an example to understand the state working and how we can define state in our projects
What are props in React ?
- Lets take an example to understand the state working and how we can define state in our projects
The code element + CSS
The HTML button tag defines a clickable button.
The CSS background-color property defines the background color of an element.
