React Components

Santhiya V

30 Jul 2022

Functional & Class Components

Functional Components:

Functional Components or stateless components are the most widely used type of components with a basic syntax of JavaScript Functions that return the JSX code or the HTML code.

They are called as stateless components because they accept the data and display it accordingly and are mainly responsible for the rendering of the UI.

Syntax

const Details=()=>{
return(
<h1>This is Santhiya , from e2e Hiring mentorship program</h1> ;
)}

Class Components :

Class based or stateful Components are the ES6 classes that extend the component class of the react library. They are known as stateful components because they are responsible for the implementation of the logic.

It has different phases of the React lifecycle including rendering, mounting, updating and unmounting stage.

Syntax

class Details extends React. Components{
render(){
return
<h1>This is Santhiya , from e2e Hiring mentorship program</h1> ;
}
}

Difference : Functional & Class Components

Functional Components

Class Components

A functional component is just a plain JavaScript pure function that accepts props as an argument and returns a React element(JSX).	A class component requires you to extend from React. Component and create a render function which returns a React element.
There is no render method used in functional components.	It must have the render() method returning JSX (which is syntactically similar to HTML)
Functional component run from top to bottom and once the function is returned it cant be kept alive.	Class component is instantiated and different life cycle method is kept alive and being run and invoked depending on phase of class component.
Also known as Stateless components as they simply accept data and display them in some form, that they are mainly responsible for rendering UI.	Also known as Stateful components because they implement logic and state.
React lifecycle methods (for example, componentDidMount) cannot be used in functional components.	React lifecycle methods can be used inside class components (for example, componentDidMount).
Hooks can be easily used in functional components to make them Stateful. example: const [name,SetName]= React.useState(‘ ‘)	It requires different syntax inside a class component to implement hooks. example: constructor(props) { super(props); this.state = {name: ‘ ‘} }
Constructors are not used.	Constructor are used as it needs to store state.