simple Promise

simplePromise.js

 //SimplePromise
function SimplePromise(fn){
  
  let resolveData = null;
  let rejectData = null;

  let thenCallback = null;

  const resolve = function(resultData) {
     resolveData = resultData;
     setTimeout(()=>{thenCallback(resolveData)},0);

  }

  let reject = function(resultData) {
     rejectData = resultData;
  }

  const then = function(cb) {
   thenCallback = cb;
  }

  fn(resolve, reject);

  return {
     resolveData, rejectData, then
  }
  
}


//Use Promise.
const result = SimplePromise(function(resolve, reject){
	setTimeout(() => {resolve("aaaa")}, 1000);
	reject("bbbbb")
});

result.then(function(data){
  console.log('data is ', data);
});