The react npm package is a JavaScript library for building user interfaces, particularly for single-page applications. It allows developers to create reusable UI components and manage the state of their applications efficiently.
Component-Based Architecture
React allows developers to encapsulate UI logic and design into components, which can then be composed to build complex user interfaces.
class Welcome extends React.Component {
render() {
return <h1>Hello, {this.props.name}</h1>;
}
}
ReactDOM.render(<Welcome name='Jane' />, document.getElementById('root'));State Management
React provides a way to manage the state within components, enabling dynamic and interactive user interfaces.
class Counter extends React.Component {
constructor(props) {
super(props);
this.state = { count: 0 };
}
increment = () => {
this.setState({ count: this.state.count + 1 });
};
render() {
return (
<div>
<p>{this.state.count}</p>
<button onClick={this.increment}>Increment</button>
</div>
);
}
}Lifecycle Methods
React components come with lifecycle methods that are invoked at specific points in a component's lifecycle, allowing developers to hook into the component's creation, updating, and destruction processes.
class Timer extends React.Component {
componentDidMount() {
this.timerID = setInterval(() => this.tick(), 1000);
}
componentWillUnmount() {
clearInterval(this.timerID);
}
tick() {
this.setState({
date: new Date()
});
}
render() {
return (
<div>
<h2>It is {this.state.date.toLocaleTimeString()}.</h2>
</div>
);
}
}Hooks
Hooks are functions that let developers 'hook into' React state and lifecycle features from function components. They provide a way to use stateful logic without writing a class.
import { useState, useEffect } from 'react';
function Example() {
const [count, setCount] = useState(0);
useEffect(() => {
document.title = `You clicked ${count} times`;
});
return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}>
Click me
</button>
</div>
);
}Vue.js is a progressive JavaScript framework used for building user interfaces. Unlike React, which is only the view layer, Vue includes a more comprehensive set of tools for building web applications, including a routing solution and state management solution.
Angular is a platform and framework for building single-page client applications using HTML and TypeScript. Angular is more prescriptive than React, providing a standard way to structure an application and including a wide array of features out-of-the-box, such as dependency injection, templating, routing, and more.
Preact is a fast, 3kB alternative to React with the same modern API. It provides the thinnest possible Virtual DOM abstraction on top of the DOM. Preact is a good choice for when performance is critical, and the application needs to be as lightweight as possible.
Svelte is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue do the bulk of their work in the browser, Svelte shifts that work into a compile step that happens when you build your app, resulting in significantly smaller and faster applications.
reactReact is a JavaScript library for creating user interfaces.
The react package contains only the functionality necessary to define React components. It is typically used together with a React renderer like react-dom for the web, or react-native for the native environments.
Note: by default, React will be in development mode. The development version includes extra warnings about common mistakes, whereas the production version includes extra performance optimizations and strips all error messages. Don't forget to use the production build when deploying your application.
import { useState } from 'react';
import { createRoot } from 'react-dom/client';
function Counter() {
const [count, setCount] = useState(0);
return (
<>
<h1>{count}</h1>
<button onClick={() => setCount(count + 1)}>
Increment
</button>
</>
);
}
const root = createRoot(document.getElementById('root'));
root.render(<Counter />);
19.1.0 (March 28, 2025)
An Owner Stack is a string representing the components that are directly responsible for rendering a particular component. You can log Owner Stacks when debugging or use Owner Stacks to enhance error overlays or other development tools. Owner Stacks are only available in development builds. Component Stacks in production are unchanged.
useId to use valid CSS selectors, changing format from :r123: to «r123». #32001href attribute is an empty string #31783getHoistableRoot() didnât work properly when the container was a Document #32321<!-- -->) as a DOM container. #32250<script> and <template> tags to be nested within <select> tags. #31837exports field to package.json for use-sync-external-store to support various entrypoints. #25231unstable_prerender, a new experimental API for prerendering React Server Components on the server #31724registerServerReference in client builds to handle server references in different environments. #32534FAQs
React is a JavaScript library for building user interfaces.
The npm package react receives a total of 31,311,044 weekly downloads. As such, react popularity was classified as popular.
We found that react demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 2 open source maintainers collaborating on the project.
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