'use strict'; /** * @ngdoc service * @name ng.$q * @requires $rootScope * * @description * A promise/deferred implementation inspired by [Kris Kowal's Q](https://github.com/kriskowal/q). * * [The CommonJS Promise proposal](http://wiki.commonjs.org/wiki/Promises) describes a promise as an * interface for interacting with an object that represents the result of an action that is * performed asynchronously, and may or may not be finished at any given point in time. * * From the perspective of dealing with error handling, deferred and promise APIs are to * asynchronous programming what `try`, `catch` and `throw` keywords are to synchronous programming. * *
 *   // for the purpose of this example let's assume that variables `$q` and `scope` are
 *   // available in the current lexical scope (they could have been injected or passed in).
 *
 *   function asyncGreet(name) {
 *     var deferred = $q.defer();
 *
 *     setTimeout(function() {
 *       // since this fn executes async in a future turn of the event loop, we need to wrap
 *       // our code into an $apply call so that the model changes are properly observed.
 *       scope.$apply(function() {
 *         deferred.notify('About to greet ' + name + '.');
 *
 *         if (okToGreet(name)) {
 *           deferred.resolve('Hello, ' + name + '!');
 *         } else {
 *           deferred.reject('Greeting ' + name + ' is not allowed.');
 *         }
 *       });
 *     }, 1000);
 *
 *     return deferred.promise;
 *   }
 *
 *   var promise = asyncGreet('Robin Hood');
 *   promise.then(function(greeting) {
 *     alert('Success: ' + greeting);
 *   }, function(reason) {
 *     alert('Failed: ' + reason);
 *   }, function(update) {
 *     alert('Got notification: ' + update);
 *   });
 * 
* * At first it might not be obvious why this extra complexity is worth the trouble. The payoff * comes in the way of guarantees that promise and deferred APIs make, see * https://github.com/kriskowal/uncommonjs/blob/master/promises/specification.md. * * Additionally the promise api allows for composition that is very hard to do with the * traditional callback ([CPS](http://en.wikipedia.org/wiki/Continuation-passing_style)) approach. * For more on this please see the [Q documentation](https://github.com/kriskowal/q) especially the * section on serial or parallel joining of promises. * * * # The Deferred API * * A new instance of deferred is constructed by calling `$q.defer()`. * * The purpose of the deferred object is to expose the associated Promise instance as well as APIs * that can be used for signaling the successful or unsuccessful completion, as well as the status * of the task. * * **Methods** * * - `resolve(value)` – resolves the derived promise with the `value`. If the value is a rejection * constructed via `$q.reject`, the promise will be rejected instead. * - `reject(reason)` – rejects the derived promise with the `reason`. This is equivalent to * resolving it with a rejection constructed via `$q.reject`. * - `notify(value)` - provides updates on the status of the promises execution. This may be called * multiple times before the promise is either resolved or rejected. * * **Properties** * * - promise – `{Promise}` – promise object associated with this deferred. * * * # The Promise API * * A new promise instance is created when a deferred instance is created and can be retrieved by * calling `deferred.promise`. * * The purpose of the promise object is to allow for interested parties to get access to the result * of the deferred task when it completes. * * **Methods** * * - `then(successCallback, errorCallback, notifyCallback)` – regardless of when the promise was or * will be resolved or rejected, `then` calls one of the success or error callbacks asynchronously * as soon as the result is available. The callbacks are called with a single argument: the result * or rejection reason. Additionally, the notify callback may be called zero or more times to * provide a progress indication, before the promise is resolved or rejected. * * This method *returns a new promise* which is resolved or rejected via the return value of the * `successCallback`, `errorCallback`. It also notifies via the return value of the * `notifyCallback` method. The promise can not be resolved or rejected from the notifyCallback * method. * * - `catch(errorCallback)` – shorthand for `promise.then(null, errorCallback)` * * - `finally(callback)` – allows you to observe either the fulfillment or rejection of a promise, * but to do so without modifying the final value. This is useful to release resources or do some * clean-up that needs to be done whether the promise was rejected or resolved. See the [full * specification](https://github.com/kriskowal/q/wiki/API-Reference#promisefinallycallback) for * more information. * * Because `finally` is a reserved word in JavaScript and reserved keywords are not supported as * property names by ES3, you'll need to invoke the method like `promise['finally'](callback)` to * make your code IE8 compatible. * * # Chaining promises * * Because calling the `then` method of a promise returns a new derived promise, it is easily * possible to create a chain of promises: * *
 *   promiseB = promiseA.then(function(result) {
 *     return result + 1;
 *   });
 *
 *   // promiseB will be resolved immediately after promiseA is resolved and its value
 *   // will be the result of promiseA incremented by 1
 * 
* * It is possible to create chains of any length and since a promise can be resolved with another * promise (which will defer its resolution further), it is possible to pause/defer resolution of * the promises at any point in the chain. This makes it possible to implement powerful APIs like * $http's response interceptors. * * * # Differences between Kris Kowal's Q and $q * * There are three main differences: * * - $q is integrated with the {@link ng.$rootScope.Scope} Scope model observation * mechanism in angular, which means faster propagation of resolution or rejection into your * models and avoiding unnecessary browser repaints, which would result in flickering UI. * - Q has many more features than $q, but that comes at a cost of bytes. $q is tiny, but contains * all the important functionality needed for common async tasks. * * # Testing * *
 *    it('should simulate promise', inject(function($q, $rootScope) {
 *      var deferred = $q.defer();
 *      var promise = deferred.promise;
 *      var resolvedValue;
 *
 *      promise.then(function(value) { resolvedValue = value; });
 *      expect(resolvedValue).toBeUndefined();
 *
 *      // Simulate resolving of promise
 *      deferred.resolve(123);
 *      // Note that the 'then' function does not get called synchronously.
 *      // This is because we want the promise API to always be async, whether or not
 *      // it got called synchronously or asynchronously.
 *      expect(resolvedValue).toBeUndefined();
 *
 *      // Propagate promise resolution to 'then' functions using $apply().
 *      $rootScope.$apply();
 *      expect(resolvedValue).toEqual(123);
 *    });
 *  
*/ function $QProvider() { this.$get = ['$rootScope', '$exceptionHandler', function($rootScope, $exceptionHandler) { return qFactory(function(callback) { $rootScope.$evalAsync(callback); }, $exceptionHandler); }]; } /** * Constructs a promise manager. * * @param {function(function)} nextTick Function for executing functions in the next turn. * @param {function(...*)} exceptionHandler Function into which unexpected exceptions are passed for * debugging purposes. * @returns {object} Promise manager. */ function qFactory(nextTick, exceptionHandler) { /** * @ngdoc * @name ng.$q#defer * @methodOf ng.$q * @description * Creates a `Deferred` object which represents a task which will finish in the future. * * @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(reject(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); } }; var wrappedErrback = function(reason) { try { result.resolve((isFunction(errback) ? errback : defaultErrback)(reason)); } catch(e) { result.reject(e); exceptionHandler(e); } }; var wrappedProgressback = function(progress) { try { result.notify((isFunction(progressback) ? progressback : defaultCallback)(progress)); } catch(e) { exceptionHandler(e); } }; if (pending) { pending.push([wrappedCallback, wrappedErrback, wrappedProgressback]); } else { value.then(wrappedCallback, wrappedErrback, wrappedProgressback); } return result.promise; }, "catch": function(callback) { return this.then(null, callback); }, "finally": function(callback) { function makePromise(value, resolved) { var result = defer(); if (resolved) { result.resolve(value); } else { result.reject(value); } return result.promise; } function handleCallback(value, isResolved) { var callbackOutput = null; try { callbackOutput = (callback ||defaultCallback)(); } catch(e) { return makePromise(e, false); } if (callbackOutput && isFunction(callbackOutput.then)) { return callbackOutput.then(function() { return makePromise(value, isResolved); }, function(error) { return makePromise(error, false); }); } else { return makePromise(value, isResolved); } } return this.then(function(value) { return handleCallback(value, true); }, function(error) { return handleCallback(error, false); }); } } }; return deferred; }; var ref = function(value) { if (value && isFunction(value.then)) return value; return { then: function(callback) { var result = defer(); nextTick(function() { result.resolve(callback(value)); }); return result.promise; } }; }; /** * @ngdoc * @name ng.$q#reject * @methodOf ng.$q * @description * Creates a promise that is resolved as rejected with the specified `reason`. This api should be * used to forward rejection in a chain of promises. If you are dealing with the last promise in * a promise chain, you don't need to worry about it. * * When comparing deferreds/promises to the familiar behavior of try/catch/throw, think of * `reject` as the `throw` keyword in JavaScript. This also means that if you "catch" an error via * a promise error callback and you want to forward the error to the promise derived from the * current promise, you have to "rethrow" the error by returning a rejection constructed via * `reject`. * *
   *   promiseB = promiseA.then(function(result) {
   *     // success: do something and resolve promiseB
   *     //          with the old or a new result
   *     return result;
   *   }, function(reason) {
   *     // error: handle the error if possible and
   *     //        resolve promiseB with newPromiseOrValue,
   *     //        otherwise forward the rejection to promiseB
   *     if (canHandle(reason)) {
   *      // handle the error and recover
   *      return newPromiseOrValue;
   *     }
   *     return $q.reject(reason);
   *   });
   * 
* * @param {*} reason Constant, message, exception or an object representing the rejection reason. * @returns {Promise} Returns a promise that was already resolved as rejected with the `reason`. */ var reject = function(reason) { return { then: function(callback, errback) { var result = defer(); nextTick(function() { try { result.resolve((isFunction(errback) ? errback : defaultErrback)(reason)); } catch(e) { result.reject(e); exceptionHandler(e); } }); return result.promise; } }; }; /** * @ngdoc * @name ng.$q#when * @methodOf ng.$q * @description * Wraps an object that might be a value or a (3rd party) then-able promise into a $q promise. * This is useful when you are dealing with an object that might or might not be a promise, or if * the promise comes from a source that can't be trusted. * * @param {*} value Value or a promise * @returns {Promise} Returns a promise of the passed value or promise */ var when = function(value, callback, errback, progressback) { var result = defer(), done; var wrappedCallback = function(value) { try { return (isFunction(callback) ? callback : defaultCallback)(value); } catch (e) { exceptionHandler(e); return reject(e); } }; var wrappedErrback = function(reason) { try { return (isFunction(errback) ? errback : defaultErrback)(reason); } catch (e) { exceptionHandler(e); return reject(e); } }; var wrappedProgressback = function(progress) { try { return (isFunction(progressback) ? progressback : defaultCallback)(progress); } catch (e) { exceptionHandler(e); } }; nextTick(function() { ref(value).then(function(value) { if (done) return; done = true; result.resolve(ref(value).then(wrappedCallback, wrappedErrback, wrappedProgressback)); }, function(reason) { if (done) return; done = true; result.resolve(wrappedErrback(reason)); }, function(progress) { if (done) return; result.notify(wrappedProgressback(progress)); }); }); return result.promise; }; function defaultCallback(value) { return value; } function defaultErrback(reason) { return reject(reason); } /** * @ngdoc * @name ng.$q#all * @methodOf ng.$q * @description * Combines multiple promises into a single promise that is resolved when all of the input * promises are resolved. * * @param {Array.|Object.} promises An array or hash of promises. * @returns {Promise} Returns a single promise that will be resolved with an array/hash of values, * each value corresponding to the promise at the same index/key in the `promises` array/hash. * If any of the promises is resolved with a rejection, this resulting promise will be rejected * with the same rejection value. */ function all(promises) { var deferred = defer(), counter = 0, results = isArray(promises) ? [] : {}; forEach(promises, function(promise, key) { counter++; ref(promise).then(function(value) { if (results.hasOwnProperty(key)) return; results[key] = value; if (!(--counter)) deferred.resolve(results); }, function(reason) { if (results.hasOwnProperty(key)) return; deferred.reject(reason); }); }); if (counter === 0) { deferred.resolve(results); } return deferred.promise; } return { defer: defer, reject: reject, when: when, all: all }; } 6' href='#n416'>416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809