Promise.js

let promiseToCleanTheRoom = new Promise(function(resolve, reject) {

  //cleaning the room

  let isClean = false;

  if (isClean) {
    resolve('Clean');
  } else {
    reject('not Clean');
  }

});

promiseToCleanTheRoom.then(function(fromResolve) {
  console.log('the room is' + fromResolve);
}).catch(function(fromReject){
	console.log('the room is' + fromReject);
})

// From: http://jsfiddle.net/u74L4n1t