error handling in ES6 generators

errors_in_generator.es.js

let price = 10;

let stockPrice = function () {
  setTimeout(function() {
    iterator.next(price++);
  }, 300);
}

let errorInStockPrice = function() {
  setTimeout(function() {
    iterator.throw(Error("oops!"));
  }, 300);
}

let stockTicker = function*() {
  try {
    price = yield stockPrice();
    console.log("price is " + price); //=> price is 10
  
    price = yield stockPrice();
    console.log("price is " + price); //=> price is 10

    price = yield errorInStockPrice();
    console.log("price is " + price); //=> price is 10
  } catch (ex) {
    console.log("error in stock-price: " + ex); //=> error in stock-price: Error: oops!
  }
};

var iterator = stockTicker();
console.log(iterator.next()); //=> {"done":false}

continuation of https://gist.github.com/deepak/40137db744bad7aa8f69