ES6 Generators with Promises

trading.js

(function(target) {
  let run = generator => {
    let sequence;
    let process = result => {
      if(result.done) { return; }
      
      result.value
        .then(value => {
          process(sequence.next(value));
        })
        .catch(err => {
          process(sequence.throw(err)); 
        });
    };
    
    sequence = generator();
    process(sequence.next());
  };
  
  target.async = {
    run
  };
}(window));

function* main() {
  try {
    let price = yield getStockPrice();
    if(price > 45) {
    	yield executeTrade();
    }
  }
  catch(ex) {
    console.error('failed', ex);
  }
}

function getStockPrice() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      //reject();
      console.log('got price');
      resolve(50);
    }, 100);
  });
}

function executeTrade() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log('executed trade');
      resolve();
    }, 100);
  });
}

async.run(main);