find type of data in javascript code example

Example 1: get type of var js

function doSomething(x) {
  if(typeof(x) === 'string') {
    alert('x is a string')
  } else if(typeof(x) === 'number') {
    alert('x is a 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,, "