ReactJS Functional vs Class Components

React allows developers to build user interfaces using components. These components can be written as Functional Components or Class Components. But which one should you use? Let's break it down.

What Are React Components?

In React, components are the building blocks of your UI. They take input (props) and return JSX, which defines the user interface.

Key Differences Between Functional and Class Components

Syntax and Simplicity
State Management
Lifecycle Methods vs. Hooks
Performance
Code Readability and Maintainability

1. Syntax and Simplicity

Functional Component Example:

const Greeting = ({ name }) => {
  return <h1>Hello, {name}!</h1>;
};

Functional components are simpler and just return JSX.

Class Component Example:

class Greeting extends React.Component {
  render() {
    return <h1>Hello, {this.props.name}!</h1>;
  }
}

Class components require a render method to return JSX.

2. State Management

Before React Hooks, only class components could manage state. Now, functional components can also manage state using useState.

Functional Component with State:

import { useState } from 'react';

const Counter = () => {
  const [count, setCount] = useState(0);
  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
};

Class Component with State:

class Counter extends React.Component {
  state = { count: 0 };
  render() {
    return (
      <div>
        <p>Count: {this.state.count}</p>
        <button onClick={() => this.setState({ count: this.state.count + 1 })}>Increment</button>
      </div>
    );
  }
}

Functional components with hooks make state management easier and more readable.

3. Lifecycle Methods vs. Hooks

Class components use lifecycle methods such as:

componentDidMount
componentDidUpdate
componentWillUnmount

Functional components achieve the same with useEffect Hook:

useEffect(() => {
  console.log("Component Mounted");
  return () => console.log("Component Unmounted");
}, []);

4. Performance

Functional components are lighter and faster since they don’t have the overhead of class components.

5. Code Readability and Maintainability

Functional components with hooks reduce boilerplate code, making it easier to read and maintain.

Which One Should You Use?

Use Functional Components for new projects as they are the modern approach.
Use Class Components only when working with older React codebases.

Conclusion

Functional components with hooks have become the standard in React development. They offer better performance, improved readability, and a more intuitive way to handle state and lifecycle logic.

Happy Coding! 🚀