Thenable login

app.js

var Utils = {};
var deferApply = function() {
  var args     = Array.prototype.slice.apply(arguments),
      f        = args[0],
      realArgs = args.slice(1)
      ;
  return new Promise(function(done, reject) {
    return f.apply(null, [done, reject].concat(realArgs));
  });
};
Utils.deferApply = deferApply;


function authAllowAll(done, reject, user_id, password){
  return done({user_id:user_id, password:password});
}

function authDefault(url){
  return function(done, reject, user_id, password, option){
    if (window.XMLHttpRequest) {
      httpRequest = new XMLHttpRequest();
      if (httpRequest.overrideMimeType) {
          httpRequest.overrideMimeType('text/plain');
      }
    } else if (window.ActiveXObject) {
      try {
          httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
            httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {}
      }
    }
    if (!httpRequest) return reject({});
    
    httpRequest.onreadystatechange = function() {     
      if (httpRequest.readyState == 4) {
        if (httpRequest.status == 200) {
          done(httpRequest.responseText)
        } else {
          reject(httpRequest.status)
        }
      }
    };
    httpRequest.open('POST', url, true);
    httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    httpRequest.send("user_id="+user_id+"&password="+password);
  }
}

function authCustom(done, reject, user_id, password, option){
  function customAuthentication(user_id,password,option){
    return true; // or false;
  }  
  var result = customAuthentication(user_id, password, option);
  if (result) return done(result);
  return reject(result);
}


function loginSuccess(result){
  console.log("success:"+result);
}
function loginFail(result){
  console.log("fail:"+result);
}
function thenableLogin(login){
  return function(user_id, password, option){
    return Utils.deferApply(login, user_id, password, option);
  }
}



var loginAction = thenableLogin(authAllowAll);
loginAction("bob","password").then(loginSuccess, loginFail)

var loginAction2 = thenableLogin(authDefault("http://localhost:9000/login"));
loginAction2("bob","bob#secret").then(loginSuccess, loginFail);