Before talking about React fundamentals we should know about react. What is React? React is an open-source front-end JavaScript library that is used for building user interfaces especially for single-page applications. It was created by Jordan Walke, a software engineer working for Facebook. …

Scope There are two types of scope- Local Scope and Global Scope. If variables are declared inside a function or block, then we will say that their scope is local and can only be accessible inside this function/block. And those variables are called Local variable. Others all the variables/functions (outside of…

Map The map function is used to loop through the array, runs the operation on its elements and returns a new array. This is just what it does. var arr= [1,2,3,4] var array=arr.map(element=> element*2) console.log(array) Here, we have an array named “arr” having 4 elements. We run the map function on…