Comparing generators with stateful objects, for performance

generator-vs-stateful.js

'use strict';
const ITER = 1e7;
let t;

function* G() {
  let i = 0;
  for (; i < ITER; i++)
    yield i;
}

function H() {
  return new HObj();
}

function HObj() {
  this._i = 0;
}
function HNext(value, done) {
  this.value = value;
  this.done = done;
}
HObj.prototype.next = function next() {
  if (this._i === ITER - 1)
    return new HNext(undefined, true);
  else
    return new HNext(this._i++, false);
};


t = performance.now();
let g = G();
while (!g.next().done);
print(performance.now() - t);

t = performance.now();
let h = H();
while (!h.next().done);
print(performance.now() - t);

// Results with d8 4.2.77 compiled for Linux x64.release
// Output:
// 392.2
// 67.6