"use strict"; // treated as all new js code version // alert(3+3) we are using nodejs not brpwser console.log(3+3+3); console.log("tansihq dhingra ");// code readibility is very important let name = "tanishq" let age = 18 let isLoggedIn = false /* primitive number = 2 ki power 53 bigint string = " " boolean = true/ false null = standalone value (value is null ) undefined = not defined symbbol = uniqueness in react */ // object console.log(typeof undefined );//undefined console.log(typeof null);//object