Function defer

test/angular/1.2/angular.js:11682–11812

()

   * @returns {Deferred} Returns a new instance of deferred.
   */
  var defer = function() {
    var pending = [],
        value, deferred;

    deferred = {

      resolve: function(val) {
        if (pending) {
          var callbacks = pending;
          pending = undefined;
          value = ref(val);

          if (callbacks.length) {
            nextTick(function() {
              var callback;
              for (var i = 0, ii = callbacks.length; i < ii; i++) {
                callback = callbacks[i];
                value.then(callback[0], callback[1], callback[2]);
              }
            });
          }
        }
      },


      reject: function(reason) {
        deferred.resolve(createInternalRejectedPromise(reason));
      },


      notify: function(progress) {
        if (pending) {
          var callbacks = pending;

          if (pending.length) {
            nextTick(function() {
              var callback;
              for (var i = 0, ii = callbacks.length; i < ii; i++) {
                callback = callbacks[i];
                callback[2](progress);
              }
            });
          }
        }
      },


      promise: {
        then: function(callback, errback, progressback) {
          var result = defer();

          var wrappedCallback = function(value) {
            try {
              result.resolve((isFunction(callback) ? callback : defaultCallback)(value));
            } catch(e) {
              result.reject(e);
              exceptionHandler(e);
            }