What is React ?

React.js, commonly known as React, is a JavaScript library for building user interfaces. It’s maintained by Facebook and a community of individual developers and companies. React is widely used for developing single-page applications where the user interface needs to be highly dynamic and responsive.

One of the key features of React is its component-based architecture. Developers can create reusable UI components, which can be composed together to build complex user interfaces. React uses a virtual DOM (Document Object Model) to efficiently update and render changes in the UI, providing a more seamless and performant user experience.

Here’s a simple example of a React component:

import React, { useState } from 'react';

const Counter = () => {
  const [count, setCount] = useState(0);

  const handleIncrement = () => {
    setCount(count + 1);

  const handleDecrement = () => {
    setCount(count - 1);

  return (
      <h1>Counter: {count}</h1>
      <button onClick={handleIncrement}>Increment</button>
      <button onClick={handleDecrement}>Decrement</button>

export default Counter;

In this example, the Counter component uses the useState hook to manage a state variable (count). It renders the current count along with two buttons to increment and decrement the count. When the user clicks on these buttons, the state is updated, triggering a re-render of the component. React efficiently updates only the parts of the DOM that have changed, providing a smooth and responsive user interface