Functional vs Class Components in React

What is React JS

React is a JavaScript library for building UIs, especially for web applications. It was created by Facebook and is presently kept up with by Facebook and a local area of individual designers and organizations. React permits designers to make reusable UI parts and productively deal with the condition of their applications. It utilizes a definitive way to deal with portraying how the UI ought to take a gander at some random moment, making it more obvious and troubleshooting code. Furthermore, React’s virtual DOM (Record Item Model) productively refreshes the genuine DOM, bringing about superior execution and a smoother client experience.

Components in React

In React, components are the structure blocks of UIs. They are reusable and independent bits of code that exemplify a particular piece of UI usefulness. Parts can be straightforward, addressing things like fastens or input fields, or they can be more intricate, addressing whole segments of a website page or application. The 2 types of major Components present in React JS are:

Functional components:

Functional components in React are JavaScript functions that return JSX (JavaScript XML) to describe the UI. They are typically used for simpler UI elements and are preferred when possible due to their simplicity and readability. Functional components are stateless, meaning they don’t have built-in state management or lifecycle methods. Here’s an example of a functional component in React:

import React from 'react';

function Greeting(props) {
  return <h1>Hello, {props.name}!</h1>;
}

export default Greeting;

In this example, the Greeting component takes a name prop and renders a greeting message with that name. Functional components can receive props as input data and use them to customize their behavior and appearance.

Functional components can also be written using ES6 arrow functions:

import React from 'react';

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

export default Greeting;

This syntax is shorter and often preferred for defining simple functional components. However, the functionality remains the same as in the previous example.

Class Component:

A class component in React is a JavaScript class that extends React.Component. Class components have additional features such as state and lifecycle methods, making them suitable for more complex UI logic.

Here’s an example of a class component in React:

import React from 'react';

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>Count: {this.state.count}</p>
        <button onClick={() => this.increment()}>Increment</button>
      </div>
    );
  }
}

export default Counter;

In this example, the Counter component maintains its own state (count) using the this.state object. The increment() method updates the state by calling this.setState(), which triggers a re-render of the component with the updated state. The current count is displayed in the UI, and clicking the button calls the increment() method to increase the count.

Class components also have access to React’s lifecycle methods, such as componentDidMount() and componentDidUpdate(), which allows developers to perform actions at specific points in the component's lifecycle, such as fetching data or performing cleanup operations.

While class components are still widely used, functional components with hooks have become more popular in recent years due to their simplicity and flexibility. However, class components remain an important part of React and are still used in many codebases.

Functional Components vs Class Components:

The significant distinction between practical parts and class parts in React lies in their language structure, elements, and how they handle state and lifecycle techniques.

1. Syntax:
Utilitarian parts are characterized as JavaScript capabilities that return JSX (JavaScript XML).
Class parts are characterized as JavaScript classes that broaden ‘React. Part’ and have a ‘render()’ strategy.

2. State:
Practical parts are stateless naturally. They don’t have inherent state the board, however, they can utilize React snares like ‘useState()’ to present nearby states.
Class parts have underlying state the board utilizing ‘this.state’ and ‘this.setState()’. They can keep up with neighborhood part state.

3. Lifecycle Techniques:
Useful parts don’t have lifecycle strategies. Nonetheless, React presented snares like ‘useEffect()’ to imitate lifecycle conduct in practical parts.
Class parts approach lifecycle techniques, for example, ‘componentDidMount()’, ‘componentDidUpdate()’, and ‘componentWillUnmount()’. These strategies permit designers to perform activities at explicit places in the part’s lifecycle.

4. Code Intricacy:
Useful parts are frequently less complex and more compact than class parts. They empower a useful programming style and are simpler to peruse and comprehend.
Class parts can turn out to be more mind-boggling, particularly while managing state the board and lifecycle strategies. They might require more standard code.

5. Performance:
Practical parts with snares might offer better execution streamlining because snares consider better code reuse and part rationale detachment.
Class parts might have slight execution above because of the extra above of class launch and lifecycle technique calls.

Conclusion:

In conclusion, both functional components and class components are integral parts of React development, each with its strengths and use cases.

Functional components are favored for their simplicity, readability, and the ability to use React hooks for state management and lifecycle behavior. They are ideal for building presentational UI components and encourage a functional programming style.

On the other hand, class components offer built-in state management and lifecycle methods, making them suitable for more complex UI logic and interactions. They have been a staple of React development for a long time and are still widely used in many codebases, especially in legacy projects.

Ultimately, the choice between functional components and class components depends on the specific requirements of the project, the developer’s preference, and the existing codebase. Both approaches have their merits, and understanding when to use each one effectively is essential for building successful React applications.