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What is react in JavaScript

Getting Started with React

React is a popular JavaScript library used to build user interfaces, particularly single-page applications. It's like a toolbox full of utilities that help developers create complex apps with less effort. Think of it as the building blocks you used to create structures as a child, but now, instead of building tangible things, you're building digital applications.

The Core Concept of React

React's main idea is to build your application's interface using smaller pieces called components. Like a jigsaw puzzle, each piece has its own job, and when put together, they form a complete picture.

For example, a social media app might have components like a News Feed, a Profile, and a Chatbox. Each component is responsible for a particular part of the application's functionality, making the code easier to understand, manage, and debug.

Why Use React?

Why not just write everything in plain JavaScript? Well, as your app grows in complexity, so does your code. It becomes difficult to keep track of what's happening and to prevent bugs. React helps manage this complexity by dividing the application into manageable, reusable pieces.

Your First React Component

Now, let's dive into some actual code. Here's how you might write a simple React component:

import React from 'react';

class HelloWorld extends React.Component {
  render() {
    return (
        Hello, world!

This is a simple component named HelloWorld that outputs "Hello, world!" when used.

Breaking Down the Code

You might be wondering what's happening in the code above. Let's break it down:

  • import React from 'react';: This line is how we bring in the React library into our file, so we can use its functionalities.
  • class HelloWorld extends React.Component {: We're declaring a new component called HelloWorld. This component is a JavaScript class that extends (inherits from) React.Component.
  • render() { ... }: This is a method (think of it as a function) that every React component must have. It tells React what to output when the component is used.
  • return ( ... );: Inside the render method, we return the JSX (a syntax that allows us to write HTML-like code in our JavaScript file) that we want to be outputted.

Using the Component

Once we have our HelloWorld component, we can use it in our application like this:

import React from 'react';
import ReactDOM from 'react-dom';
import HelloWorld from './HelloWorld';

ReactDOM.render(<HelloWorld />, document.getElementById('root'));

Here, ReactDOM.render is a function that takes two arguments: the component you want to render and the HTML element where you want to render it. In this case, it's rendering our HelloWorld component inside the HTML element with the id 'root'.


At its core, React is like a master chef, expertly coordinating the various components of a complex dish to create a delightful user experience. It provides a structured way to create large, complex web applications by allowing you to break them down into smaller, manageable, and reusable pieces - the components.

By understanding the basics of React and getting your hands dirty with some code, you've taken a significant first step into the world of modern web development. Like any new skill, it will take some time to get comfortable with React. But don't worry. The more you use it, the more natural it becomes.

So, why not create your own React application now? Remember, the best way to learn is by doing. Happy coding!