Question

我正在尝试使用我的控制器方法中的参数调用服务，并且我收到一条错误消息，指出它不是函数。这是我的代码：

(function (){

angular.module('app.uploadedReleases')
        .controller('UploadedReleasesController', UploadedReleasesController)
        .controller('ModalController', ModalController);


UploadedReleasesController.$inject = ['$log', '$scope', '$modal', 'ReleaseService', 'TrackService'];
function UploadedReleasesController ($log, $scope, $modal, releaseService, trackService){

        vm.selectTrack = selectTrack;

       function selectTrack(album, track, index){

        trackService.currentTrack(album.slug, track.fileName).then(function(responseValue){
            vm.temp = responseValue;
        });
        vm.formTrack = vm.selected.track;
    }
}

这是我的服务，名为trackService：

angular.module('app.services')
        .service('TrackService', TrackService);

TrackService.$inject = ['$http', '$q'];

function TrackService($http, $q){
    var trackService = {};

    var releasesUrl = 'http://localhost:8080/api/releases';
    trackService.currentTrack = currentTrack;

        function currentTrack(releaseSlug, trackSlug){
        var trackUrl = releasesUrl + '/'+ releaseSlug + '/' + trackSlug + '/track';
        var deferred = $q.defer();

        $http.get(trackUrl).then(function(trackResponse){
            return deferred.resolve(trackResponse);
        }, function(error){
            return deferred.reject({msg: 'Error while getting the current track details'})
        });
      return deferred.promise;
    }
}

我知道为什么我会在控制器中收到错误：TypeError: trackService.currentTrack is not a function

Answer 1

@Pankaj Parkar的回答是正确的，因为您应该从currentTrack返回一个承诺，以便在您的控制器中链接then。

但是，要回答有关TypeError的问题，请在TrackService中混合出厂和服务语法。

要使其成为工厂，请返回已公开函数的地图：

function TrackService($http, $q){
    var trackService = {};
    trackService.currentTrack = currentTrack;

    function currentTrack(releaseSlug, trackSlug){
        //...
    }

    return trackService;
}

并使用.factory('TrackService', TrackService);声明。

要使其成为服务，请将公开的函数添加到this：

function TrackService($http, $q){
    this.currentTrack = currentTrack;

    function currentTrack(releaseSlug, trackSlug){
        //...
    }
}

并使用.service('TrackService', TrackService);声明。

Answer 2

我要说的第一件事是，你正在创建一个服务然后你应该将方法绑定到this上下文，而不是创建对象。

var trackService = {};

会改为

var trackService = this;

但是从服务返回自定义对象也没错。所以在目前的情况下你错过了回来。在您的服务代码末尾添加

return trackService

仍然困惑如何服务＆amp;工厂工作，我建议你在this answer

上阅读

您应该使用自定义方式创建的trackService.currentTrack方法返回承诺。

trackService.currentTrack = currentTrack;
function currentTrack(releaseSlug, trackSlug){
    var trackUrl = releasesUrl + '/'+ releaseSlug + '/' + trackSlug + '/track';
    var deferred = $q.defer();
    $http.get(trackUrl).then(function(trackResponse){
        return deferred.resolve(trackResponse);
    }, function(error){
        return deferred.reject({msg: 'Error while getting the current track details'})
    });
    return deferred.promise; //returned promise
}

相反，你应该做你的自定义承诺，这被认为是在$http.get方法返回承诺的情况下实现的反模式，你应该利用它。

重构版本

trackService.currentTrack = currentTrack;
    function currentTrack(releaseSlug, trackSlug){
    var trackUrl = releasesUrl + '/'+ releaseSlug + '/' + trackSlug + '/track';
    return $http.get(trackUrl).then(function(trackResponse){
        return trackResponse;
    }, function(error){
        return {msg: 'Error while getting the current track details'};
    });
}

AngularJS TypeError：“track”不是函数

2 个答案: