example.js

Object.defineProperty(Number.prototype,Symbol.iterator,{
  *value({ start = 0, step = 1 } = {}) {
     var inc = this > 0 ? step : -step;
     for (let i = start; Math.abs(i) <= Math.abs(this); i += inc) {
        yield i;
     }
  },
  enumerable: false,
  writable: true,
  configurable: true
});

for (let i of [...8]) {
  console.log(i);
}

// Or even just:
for (let i of 8) {
  console.log(i);
}