Angular - .finally() 是否在链式承诺决策树中的每条路径的末尾调用？

Question

我有以下连锁的承诺序列：

$scope.promisesInProgress = true
myService.myFirstPromise(id)
    .then(function(data){
        $scope.firstResponse = data;
        return myService.mySecondPromise(id);
    })
    .then(function(data){
        $scope.secondResponse = data;
    })
    .finally(function(){
        $scope.promisesInProgress = false;
    });

无论前两个promise成功/失败，是否都在最后调用了finally()回调函数？

例如，如果 myFirstPromise() return 发出 400 响应，mySecondPromise() 将永远不会被调用 - 但我假设 finally() 块仍会被抛出？如果 mySecondPromise() returns a 400（并且 $scope.secondResponse 从未设置）并且如果两个承诺 return 200s.

Answer 1

Angular 1.x $q 服务灵感来自 Kris Kowal 的 Q，基于 docs:

finally(callback, notifyCallback) – 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 for more information.

所以是的，无论 myFirstPromise 解决还是拒绝，finally() 块都会被调用

已更新，

请注意，myFirstPromise 的 finally() 块将在 mySecondPromise 解决（或拒绝）之前调用，因为 myFirstPromise 和 mySecondPromise 是不同的 promise 实例，mySecondPromise 在 myFirstPromise 解决后创建的 promise 实例

Answer 2

我写了一个 Jasmine 测试来查看 finally() 块是否在每个函数执行时被调用，无论链接的承诺返回什么。

describe('myController Test Suite', function(){

    var q, scope, deferred, myService;

    // Initialize the Pointivo module
    beforeEach(function(){
        module('myApp');
    });

    // Mock out fake service
    beforeEach(function(){
        myService = {
            myFirstPromise: function(){
                deferred = q.defer();
                // TEST ME
                deferred.resolve('first promise response');
                return deferred.promise;
            },
            mySecondPromise: function(){
                deferred = q.defer();
                // TEST ME
                deferred.resolve('second promise response');
                return deferred.promise;
            },
            myThirdPromise: function(){
                deferred = q.defer();
                // TEST ME
                deferred.resolve('third promise response');
                return deferred.promise;
            }
        };
        spyOn(myService, 'myFirstPromise').and.callThrough();
        spyOn(myService, 'mySecondPromise').and.callThrough();
        spyOn(myService, 'myThirdPromise').and.callThrough();
    });

    // Assign controller scope and service references
    beforeEach(inject(function($controller, $rootScope, $q){
        scope = $rootScope.$new();
        q = $q;
        $controller('myController', {
            $scope: scope,
            myService: myService
        });
    }));

    describe('finally test', function(){
        it('should always hit the finally statement', function(){
                scope.finallyStatementFlag = false;
            scope.test();
            scope.$apply();
            expect(scope.finallyStatementFlag).toBeTruthy();
        });
    });

});

以上假设控制器看起来像：

myApp.controller('myController', function($scope, myService){

    $scope.finallyStatementFlag = false;

    $scope.test = function(){
        myService.myFirstPromise()
            .then(function(data){
                console.log(data);
                return myService.mySecondPromise()
            })
            .then(function(data){
                console.log(data);
                return myService.myThirdPromise();
            })
            .then(function(data){
                console.log(data);
            })
            .finally(function(){
                console.log('finally statement');
                $scope.finallyStatementFlag = true;
            });
    }

});

即使您在我们定义 myService.[=18 的 beforeEach() 回调中将任何或所有 deferred.resolve() 更改为 deferred.reject()，以上内容也会通过=]

Fiddle example

Angular - .finally() 是否在链式承诺决策树中的每条路径的末尾调用？

Angular - Is .finally() Called At the End of Every Path in a Chained Promise Decision Tree?

angularjs

angular-promise