simple generator

generator.es.js

let price = 10;

let stockPrice = function () {
  // iterator.next(price++); // throws a "Generator is already running" error
  return price++
}

let oops = function () {
  throw new Error("oops!");
}

let stockTicker = function*() {
  yield stockPrice();
  yield stockPrice();

  // throw new Error("oops!"); // same as calling "oops" as below
  oops();
};

var iterator = stockTicker();
console.log(iterator.next()); //{"value":10,"done":false}
console.log(iterator.next()); // {"value":11,"done":false}
console.log(iterator.next()); // oops!

continuation of https://gist.github.com/deepak/f41c622efc574ebab7c1