how to find data type in js code example

Example 1: check data type in javascript

typeof("string"); //string
typeof(123); //number

Example 2: javascript all type of data

let a = ["A", 1, true, [], [2, 'x'],{},{a:'B'}, NaN, undefined, null];
let s = a.toString();
console.log(s);//"A,1,true,,2,x,[object Object],[object Object],NaN,, "