Control the flow of asynchronous calls with ES6 generator functions

index.js

/**
 * get - XHR Request
 */
 
let get = function (url) {
  return function (callback) {
    let xhr = new XMLHttpRequest();
    xhr.open('GET', url);
    xhr.onreadystatechange = function() {
      let response = xhr.responseText;
      if(xhr.readyState != 4) return;
      if (xhr.status === 200) {
        callback(null, response);
      }
      else {
        callback(response, null);
      }
    };
    xhr.send();
  };
};


/**
 * getTweets (Generator)
 */
 
let getTweets = function* () {

  let data;
  let totalTweets = [];

  // get the 1st tweet
  data = yield get('https://api.myjson.com/bins/2qjdn');
  totalTweets.push(data);

  // now get the 2nd tweet
  data = yield get('https://api.myjson.com/bins/3zjqz');
  totalTweets.push(data);

  // then get the 3rd tweet
  data = yield get('https://api.myjson.com/bins/29e3f');
  totalTweets.push(data);

  console.log(totalTweets);
}

// initialise iterator

let it = getTweets();

// kick it off 

let result = it.next();
result.value(function(err, res){
  if (err) console.log('do something with this error', err);
  
  // get the response and pass it in as a param to be saved
  let result = it.next(res);
  result.value(function(err, res){
    if (err) console.log('do something with this error', err);
    
    // get the response and pass it in as a param to be saved
    let result = it.next(res);
    result.value(function(err, res){
      if (err) console.log('do something with this error', err);
      
      // get the response and pass it in as a param to be saved
      let result = it.next(res);
    })
  });
});

// ^ Remind you of anything? Gross right?!