React Overview
React is an open-source front-end JavaScript library for building user interfaces or UI components. It is maintained by Facebook and a community of individual developers and companies. React can be used as a base in the development of single-page or mobile applications.
Key Features
- Component-Based: Build encapsulated components that manage their own state.
- Declarative: Design simple views for each state in your application.
- Virtual DOM: Efficiently updates and renders just the right components when data changes.
- JSX: JavaScript syntax extension that allows writing HTML-like code in JavaScript.
- One-Way Data Flow: Data flows down from parent to child components via props.
- Hooks: Let you use state and other React features without writing classes.
- Rich Ecosystem: Large community and many third-party libraries available.
Common Use Cases
Single Page Applications
React is ideal for building dynamic SPAs with complex user interactions.
Progressive Web Apps
Create PWAs with React that work offline and provide app-like experiences.
Cross-Platform Mobile Apps
React Native allows building native mobile apps using React.
Interactive Dashboards
Build complex data visualization dashboards with real-time updates.
Example Code
// Functional component with hooks example
import React, { useState, useEffect } from 'react';
function Counter() {
const [count, setCount] = useState(0);
const [isEven, setIsEven] = useState(false);
useEffect(() => {
// Update isEven when count changes
setIsEven(count % 2 === 0);
}, [count]);
return (
<div className="counter">
<h2>Counter: {count}</h2>
<p>This number is {isEven ? 'even' : 'odd'}</p>
<button onClick={() => setCount(count + 1)}>
Increment
</button>
<button onClick={() => setCount(count - 1)}>
Decrement
</button>
</div>
);
}
export default Counter;