Functional Components vs Class components in React

Introduction

React offers two main ways to define components: Functional and Class-based. Over time, functional components have become the standard, especially with the introduction of React Hooks in version 16.8. In this post, we’ll break down both types, explore their differences, and help you understand when and why to use one over the other.

🔹 What Are React Components?

Components are the building blocks of any React application. Each component represents a piece of UI. There are two primary types:

• Functional Components

• Class Components

🔹 Functional Components

✅ Definition
A functional component is a plain JavaScript function that returns JSX. Before hooks, functional components were limited and couldn't manage state or side effects — now they can do almost everything class components can.

import React from 'react';

function App(){
    return(
       <div>
         <h1>Hello World</h1>
       </div>
 )
}
export default App;

✅ Advantages

• Concise and easier to read

• No need for this keyword

• Full feature support via Hooks

• Preferred in modern React development

🔹 Class Components

✅ Definition
Class components are ES6 classes that extend from React.Component. They have a render() method and access to lifecycle methods.

import React, { Component } from 'react';

class App extends Component{
      render(){
         return(
            <div>
               <h1>Hello World</h1>
            </div>
      )
}
export default App;

❗ Drawbacks

• More boilerplate

• Use of this can be confusing

• Lifecycle methods are less intuitive than hooks

🔹 Comparison Table

Feature	Functional Component	Class Component
Syntax	Function/Arrow Function	ES6 Class
State	useState Hook	this.state
Side Effects	useEffect Hook	Lifecycle methods
this keyword	❌ Not required	✅ Required
Boilerplate	Minimal	Verbose
Code Reusability	Custom Hooks	HOCs, Render Props
Performance	Slightly better (modern)	Slightly heavier

🔹 When to Use Functional Components

• In modern React projects (React 16.8+)

• When you want concise, maintainable code

• When using hooks for shared logic

🔹 When Class Components Are Still Useful

• Maintaining legacy codebases

• Understanding React's history and lifecycle

• Some advanced patterns still use classes (e.g., Error Boundaries)

🔹 Conclusion

While both functional and class components are valid in React, the trend has shifted toward using functional components thanks to the power of hooks. They make code easier to understand, test, and maintain.

If you’re starting a new project or migrating old code, go with functional components — they're the future of React.

✍️ Final Thoughts

React continues to evolve, and staying updated is essential. Embracing functional components and hooks will help you write cleaner, more efficient React apps.