Class Components vs Functional Components: Which Should You Use?

Class Components vs Functional Components: Which Should You Use?

React has two ways to write components: class components and functional components. Beginners are confused about which to use. The honest answer is simple, but the reasoning matters.

What Class Components Are

Class components are ES6 classes that extend React.Component. They hold state in this.state, update it with this.setState, and use lifecycle methods like componentDidMount. They were the standard before 2019.

What Functional Components Are

Functional components are JavaScript functions that return JSX. Before hooks, they were stateless and could only receive props. With hooks, they can hold state and run side effects, which made them as powerful as class components.

Why Functional Components Won

Hooks gave functional components every capability class components had, with less boilerplate, easier code reuse through custom hooks, and better tooling support. The React team and ecosystem moved to functional components.

Which to Use Today

Use functional components for all new code. They are the modern standard, simpler to read and write, and what every modern React tutorial, course, and codebase uses.

Should You Still Learn Class Components?

Yes, enough to read them. A lot of existing code, older tutorials, and some interview questions use class components and lifecycle methods. You do not need to write them, but you should understand them.

The Common Mistake

Beginners sometimes mix class and functional components in the same project for no reason, or try to use hooks inside class components, which is not allowed. Pick functional components and stay consistent.

The Verdict

For new code, always functional components with hooks. For understanding existing code and interviews, learn class components and lifecycle methods. You write functional; you read class.