ES2015 for of loop - https://www.leeboonstra.com/developer/sencha-ecmascript-2015/

ES2015-for-of.js

var array = [10, 20, 30];
var map = new Map([["a", 1], ["b", 2], ["c", 3]]);

for (var i of array) {
  console.log(i);
  //10
  //20
  //30
}

for (var entry of map) {
  console.log(entry);
  //Array [ "a", 1 ]
  //Array [ "b", 2 ]
  //Array [ "c", 3 ]
}