Benchmark measures speed of every possible looping operators in javascript (i.e.: for(.;.;.),for of, for in, native .forEach() ) over Array and Map instance

Array.loop.bench.js

console.clear && console.clear();
Array.prototype.each = function (fn,this_){
  if(this.length <=0 || fn == undefined) return;
  let i = -1
  if (this_) fn = fn.bind(this_);
  do { fn(this[i],i) }
  while (i++ < this.length)
};

var pow = 16
var arr = Array.apply(null,{length: Math.pow(2,pow)}).map((e,i) => ['elem '+i,i]);
var fn = function(elem,i){};
console.time('while')
var i = 0;
while (i < arr.length) { fn(arr[i],i++) }
console.timeEnd('while')

console.time('for of')
var elem = undefined
for (elem of arr) { fn(elem) }
console.timeEnd('for of');


console.time('for itar')
for (var i = 0;i < arr.length; i++) { fn(arr[i],i) }
console.timeEnd('for itar')

console.time('for in')
var elem = undefined
for (elem in arr) { fn(arr[elem]) }
console.timeEnd('for in')

console.time('arr.forEach')
arr.forEach(fn);
console.timeEnd('arr.forEach')

console.time('arr.each')
arr.each(fn);
console.timeEnd('arr.each')


var m = new Map(arr);
console.time('Map while')
var entries = m.entries()
var done = false;
var pair;
while(!done) {
    pair = entries.next();
    done = pair.done
}
console.timeEnd('Map while')

console.time('Map forEach')
m.forEach(fn)
console.timeEnd('Map forEach')