more about custom hooks https://reactjs.org/docs/hooks-custom.html custom hooks like regular react hooks so you can create your own hooks and make them reusable entities. one note hook name should start with the use keyword. working link https://stackblitz.com/edit/react-wk6ueh import React , { Component , useEffect , useState } from 'react' ; import { render } from 'react-dom' ; import Hello from './Hello' ; import './style.css' ; //usefetchData hook uses to fetch data from any api const usefetchData =( url )=>{ //check status data is loaded or not const [ status , setStatus ]= useState ( false ) //set data when its loaded sucessfully const [ data , setData ]= useS...