Functional vs. Class Components

In React, there are two primary ways to define components: Functional Components and Class Components. Both have different strengths and purposes in the React ecosystem.

🧠 Functional Components:

Functional components use hooks (introduced in React 16.8) for managing state, side effects, and context.
Simplicity: They are concise, easier to read, and have less boilerplate code compared to class components.
Hooks: With hooks like useState, useEffect, and useMemo, functional components can manage state and side effects without the need for class syntax.
Easier to test: Since they are just functions, functional components are easier to unit test.
Performance: Functional components typically have better performance because they have less overhead.

Example of a functional component:

javascript1const Counter = () => {
2  const [count, setCount] = useState(0);
3  return <button onClick={() => setCount(count + 1)}>{count}</button>;
4}

🧠 Class Components:

Class components were the original way to define components in React.
Lifecycle Methods: They rely on lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount to handle side effects.
Verbosity: Class components require more boilerplate code.
State Management: State is managed using the this.state object and this.setState() method.

Example of a class component:

javascript1class Counter extends React.Component {
2  constructor() {
3    super();
4    this.state = { count: 0 };
5  }
6
7  increment = () => {
8    this.setState({ count: this.state.count + 1 });
9  }
10
11  render() {
12    return <button onClick={this.increment}>{this.state.count}</button>;
13  }
14}

Conclusion:

Functional components are now the recommended approach due to their simplicity, ease of testing, and support for hooks.
Class components are still supported but are generally seen as more verbose and harder to maintain.