ReactJS: Functional Components vs Class Components

In ReactJS, functional components and class components are two ways of creating components to build the user interface.

Functional Components:

Functional components are simple JavaScript functions that accept props as an argument and return React elements. They are also known as stateless components because they do not have state or lifecycle methods.

Class Components:

Class components are ES6 classes that extend from React.Component. They have their own internal state and lifecycle methods like componentDidMount, componentDidUpdate, componentWillUnmount, etc.

Scenarios:

Functional components are preferred when you need a simple component without state or lifecycle methods. They are easier to read, write, and test. Use functional components for presentational components or components that just render UI based on props.

Class components are suitable for more complex components that need state management, lifecycle methods, and require features like local state or refs. You should use class components when you need to implement features like componentDidMount, setState, or have complex logic inside the component.

Starting from React 16.8, you can also use React Hooks in functional components to manage state and lifecycle effectively.