gistfile1.js

//---------Promise----------
var Promise = function() {
   this.__successCallbacks = [];
   this.__errorCallbacks = [];
   this.__value = undefined;
   this.__state = 'pending';

   //state = pending, success, error
   this.then = function(successHandler, errorHandler) {
       this.done(successHandler);
       this.fail(errorHandler);
       return this
   };
   this.done = function(callback) {
       if (callback && typeof callback === 'function') {
           this.__successCallbacks.push(callback);
           if (this.__status === 'success') {
               callback.apply(this, this.__value)
           }
       }
       return this
   };
   this.fail = function(callback) {
       if (callback && typeof callback === 'function') {
           this.__errorCallbacks.push(callback);
           if (this.__status === 'error') {
               callback.apply(this, this.__value)
           }
       }
       return this
   };
   this.getState = function() {return this.__state};
   this.__setState = function(args) {
       if (this.__state !== 'pending') {return this}
       this.__state = args.status;
       this.__value = args.value;
       this['__' + this.__state + 'Callbacks'].forEach(function(callback) {
           callback.apply(this, this.__value)
       }.bind(this));
       console.log('---', this);
       return this
   }
};

//---------Deffered---------

var Deffered =  function() {
  var promise = new Promise();

  this.resolve = function() {
      promise.__setState({
          status: 'success',
          value: arguments
      })
  };
  this.reject = function(err) {
      promise.__setState({
          status: 'error',
          value: [err]
      })
  };
  this.promise = function() {return promise}

};

//--------Ajax---------------
var Get = function (options) {
    var xmlhttp, deffered = new Deffered();

    if (window.XMLHttpRequest) {
        // code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp = new XMLHttpRequest();
    } else {
        // code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    xmlhttp.onreadystatechange = function (ev) {
        if (xmlhttp.readyState == 4) {
            if (xmlhttp.status == 200) {
                if (options.success != null && typeof options.success === 'function') {
                    options.success.call(this.response, this, ev);
                }
                deffered.resolve(this.response, this, ev)
            } else {
                if (options.error != null && typeof options.error === 'function') {
                    options.error.apply(this, arguments)
                }
                deffered.reject(new Error(xmlhttp.message || 'some trouble with ajax'))
            }
        }
    };

    xmlhttp.open("GET", options.url, true);
    xmlhttp.send();
    return deffered.promise()
};