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Differences Between Functional Components and Class Components

Last Updated : 13 Nov, 2025

In React, components are building blocks of UI and can be defined as either Functional Components or Class Components. While both serve the same purpose, they differ in syntax, state management, and lifecycle methods. Functional components are simpler and use React Hooks, while class components are feature-rich but more complex.

Functional Components

A functional component is a simpler way to define components in React using JavaScript functions. Unlike class components, functional components do not require a constructor or lifecycle methods. They are typically used for components that are presentational and do not manage complex state or lifecycle events.

Syntax

const Car=()=> {
 return <h2>Hi, I am also a Car!</h2>;
}

Output

👁 Image

In this code

  • Functional Component: FunctionalComponent uses useState to manage the count state, starting at 0.
  • Increase Function: The increase function adds 1 to count when the button is clicked.
  • UI: Displays a heading, current count, and an "Add" button to trigger the state update.

For more details follow this article => React Functional Components

Class Component

A class component is one of the two ways to define components in React, the other being functional components. Class components are ES6 classes that extend React.Component and can hold and manage internal state.

Syntax

class Car extends React.Component {
 render() {
 return <h2>Hi, I am a Car!</h2>;
 }
}

Output

👁 Image

In this code

  • Class Component: ClassComponent extends React.Component.
  • State: count state is initialized to 0 in the constructor.
  • Increase Method: Increments count by 1 when the button is clicked.
  • UI: Displays heading, count, and "Add" button.

For more details follow this article => React Class Components

Functional Components vs Class Components

Here is a detailed comparison of Functional Components and Class Components based on various features.

Feature

Functional Components

Class Components

State Management

It can use Hooks like useState, useReducer

It uses this.state and this.setState()

Lifecycle Methods

It uses useEffect Hook for lifecycle methods

It uses traditional lifecycle methods like componentDidMount, componentWillUnmount

Rendering

Returns JSX directly inside the function

Uses a render() method to return JSX

Performance

Faster and more lightweight due to simpler structure

Slightly heavier due to the overhead of class instances

Hooks

Can use React hooks (useState, useEffect, etc.)

Cannot use hooks; relies on lifecycle methods and state

This Keyword

Does not use this keyword

Uses this to access props and state

Code Complexity

Less boilerplate code, easier to write and understand

More boilerplate code, especially for state and methods

Event Handling

Simple and direct event handling

Requires method binding for event handling

When to Use Each Component

Let's compare Functional Components and Class Components and their usage:

Functional Components

Functional components are recommended for most new development due to their simplicity, performance, and flexibility.

  • Recommended for most new development: Functional components, especially with hooks, are now the preferred choice for new React projects due to their simplicity, performance, and flexibility.
  • Ideal for smaller components: If the component is simple and doesn’t need complex lifecycle methods or state management, a functional component is the best choice.
  • Modern React development: Since React hooks were introduced, functional components are used extensively in modern React development.

Class Components

Class components are still used in legacy projects and for certain use cases involving lifecycle methods.

  • Legacy code: Class components are still common in older React codebases. If you’re working with an existing project that uses class components, you may need to continue using them.
  • Compatibility with third-party libraries: Some third-party libraries may still rely on class components or need to be used with class-based components.
  • LifeCycle Methods: For components where lifecycle events like componentDidMount or componentDidUpdate are essential.

Note: Generally, we prefer using functional components in React due to their simplicity, especially with hooks for state and side effects management.

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