Encoding Haskells `Maybe` or Scala's `Option` type in JavaScript using the new generators (es6)

options.js

function Option(value) {
  this.value = value;
  this.some = arguments.length == 1
}

Option.none = new Option()
Option.some = v => new Option(v)
Option.prototype.iterator = function () {
  if (this.some) yield this.value
}

var opts = [Option.some(3), Option.none, Option.some(4)]

for (let el of opts)
for (let v of el)
  console.log(v)
  
// yields:
//   3
//   4

// using the spread operator to unpack the option
console.log( [1, 2, ...Option.some(3), ...Option.none, 4] )
// yields: [1, 2, 3, 4]



// Example: working with computations, that might fail

function rand() {
  return Math.random() * 20
}

function f1(x) {
  if (x > 10)
    return Option.some(x)
  else
    return Option.none
}

function f2(x, y) {
  if (y == 0)
    return Option.none
  else
    return Option.some(x / y);
}

for (let x of f1(rand()))
for (let y of f1(rand()))
for (let res of f2(x, y))
  console.log( res )