Stateful functional components in React using useState Hook

In this tutorial, we are going to learn about how to use the state in functional components by using useState() hook.

What are Hooks?

Hooks are the new feature in react which allow us to use the react features in functional components without using the class-based components.

Example: useState hook is used to add the state in functional components

Hooks are currently in React v16.8.0-alpha.0.

useState hook

useState hook helps us to add the state in functional components.

example:

import {useState} from 'react';

function Counter(){

 let [number,setCount ] = useState(0);
   return (
       <div>
        <h1>{number}</h1>
        <button onClick={()=>setCount(number+1)} >Increment</button>        <button onClick={()=>setCount(number-1)} >Deccrement</button>       </div>
   )
}

In the above code we first imported useState function.

useState function will accept one argument which is an initial state so that we passed 0 as an initial state.

What does useState return?

if we invoke a useState function with the initial state it will return an array with two values first one is current state and the second one is function which is used to update the current state.

let [number,setCount ] = useState(0);