What is a Component?

• Component is independent and reusable bits of code.
• Components let you break up the user interface into separate pieces / that can then be reused / and handled independently.

Class Component v/s Function Component

Class Component :

• To define a React component / as a class, extend the built-in Component class / and define a render method.

class Welcome extends React.Component {
    render() {
        return <h1>Hello, {this.props.name}</h1>;
    }
}

• To use Lifecycle methods in class Components.
• Little complex compared with Functional Components.

Class component without state

Class component with state

Function Component :

• React functional component is a simple JavaScript function / that accepts props and returns a React element.
• These functions may or may not receive data as parameters.

// Normal function 
function Welcome () {
        return <h1>Hello, {this.props.name}</h1>;
    }


//Arrow function
 const Welcome  = () =>  {
        return <h1>Hello, {this.props.name}</h1>;
    }

• Function components are called stateless components (Before Introducing hook).
• Access state and other react features (lifecycle methods) using hooks.
• Easy to create Function components.

function component without state

function component with state