Function qFactory

test/angular/1.6/angular.js:17258–17648

* Constructs a promise manager. * * @param {function(function)} nextTick Function for executing functions in the next turn. * @param {function(...*)} exceptionHandler Function into which unexpected exceptions are passed for * debugging purposes. * @param {boolean=} errorOnUnhandledRejection

(nextTick, exceptionHandler, errorOnUnhandledRejections)

 * @returns {object} Promise manager.
 */
function qFactory(nextTick, exceptionHandler, errorOnUnhandledRejections) {
  var $qMinErr = minErr('$q', TypeError);
  var queueSize = 0;
  var checkQueue = [];

  /**
   * @ngdoc method
   * @name ng.$q#defer
   * @kind function
   *
   * @description
   * Creates a `Deferred` object which represents a task which will finish in the future.
   *
   * @returns {Deferred} Returns a new instance of deferred.
   */
  function defer() {
    return new Deferred();
  }

  function Deferred() {
    var promise = this.promise = new Promise();
    //Non prototype methods necessary to support unbound execution :/
    this.resolve = function(val) { resolvePromise(promise, val); };
    this.reject = function(reason) { rejectPromise(promise, reason); };
    this.notify = function(progress) { notifyPromise(promise, progress); };
  }


  function Promise() {
    this.$$state = { status: 0 };
  }

  extend(Promise.prototype, {
    then: function(onFulfilled, onRejected, progressBack) {
      if (isUndefined(onFulfilled) && isUndefined(onRejected) && isUndefined(progressBack)) {
        return this;
      }
      var result = new Promise();

      this.$$state.pending = this.$$state.pending || [];
      this.$$state.pending.push([result, onFulfilled, onRejected, progressBack]);
      if (this.$$state.status > 0) scheduleProcessQueue(this.$$state);

      return result;
    },

    'catch': function(callback) {
      return this.then(null, callback);
    },

    'finally': function(callback, progressBack) {
      return this.then(function(value) {
        return handleCallback(value, resolve, callback);
      }, function(error) {
        return handleCallback(error, reject, callback);
      }, progressBack);
    }
  });