how to know type of data in javascript code example

Example 1: type of variable js

// get type of variable

var number = 1
var string = 'hello world'
var dict = {a: 1, b: 2, c: 3}

console.log(typeof number) // number
console.log(typeof string) // string
console.log(typeof dict)   // object

Example 2: check data type in javascript

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

Example 3: 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,, "