Square each number in an array in javascript

Question

I\'m trying to square each number in an array and my original code didn\'t work. I looked up another way to do it, but I\'d like to know WHY the original code didn\'t work.<

Answer 1

Use embedded for , for pretty syntax :

      var arr=[1,2,3,4] ;
      [for (i of arr) i*i ]; 

      //OUT : > [1,4,9,16]