Question

我想要实现的目标是：

调用我的服务以检索与医生相关的约会类型（未修复的类型数）中的所有约会
如果有3种约会类型，则会有3次异步通话
在所有3个承诺都已解决后，使用$ q.all（）返回单个承诺

appointmentService

this.getAllDoctorAppointments = function (doctor, appointmentTypeArray) {

        var promises = [];

        angular.forEach(appointmentTypeArray, function (appointmentType) {

            var defer = $q.defer();

            $http.get('/appointments/?doctorName=' + doctor + '&apptType=' + appointmentType)
                .success(function (listOfAppointments) {

                    defer.resolve(listOfAppointments);
                    promises.push(defer.promise);

                });
        });

        return $q.all(promises);

    };

在我的控制台日志中，appointmentType返回[]。发生这种情况是因为空洞的承诺＆＃39;即使在进行3次异步调用之前，也会返回数组。我对承诺的概念还很陌生，最好的方法是什么？谢谢！

$scope.getAllDoctorAppointments = function (doctor, appointmentTypeArray) {

    appointmentService.getAllDoctorAppointments(doctor, appointmentTypeArray)

        .then(function (appointmentType) {

//could take in any number. hardcoded 3 just for testing.
console.log(appointmentType)

            angular.forEach(appointmentType[0], function (xRay) {
                $scope.xRayAppts.events.push(xRay);
            });

            angular.forEach(appointmentType[1], function (ctScan) {
                $scope.ctScanAppts.events.push(ctScan);
            });

            angular.forEach(appointmentType[2], function (mri) {
                $scope.mriAppts.events.push(mri);
            });

        });

};

Answer 1

this.getAllDoctorAppointments = function (doctor, appointmentTypeArray) {
    var promises = [];

    angular.forEach(appointmentTypeArray, function (appointmentType) {

        promises.push($http.get('/appointments/?doctorName=' + doctor + '&apptType=' + appointmentType)
            .success(function (listOfAppointments) {
                return listOfAppointments;
            });
        );
    });

    return $q.all(promises);
};

$http.get返回您想要收集的承诺，在这种情况下不需要新的延期。

Answer 2

未将promise添加到数组中，因为将其添加到数组promises.push(defer.promise);的代码位于您尝试推迟的事物的结果代码中。因此，承诺不会被添加到承诺列表中，直到执行完毕后才会执行！

所以你可以在成功通话之外移动该推线看起来像这样：

angular.forEach(appointmentTypeArray, function (appointmentType) {

        var defer = $q.defer();

        $http.get('/appointments/?doctorName=' + doctor + '&apptType=' + appointmentType)
            .success(function (listOfAppointments) {

                defer.resolve(listOfAppointments);

            });
        promises.push(defer.promise);

    });

或者，您可以像lcycool建议的那样，直接将$http.get(...).success(...)调用直接添加到数组中。

Angular Promises使用空数组

我想要实现的目标是：

2 个答案: