javascript - 调用工厂定义的方法返回未定义的值/ promise

Question

我在 Angular 中有一个错综复杂的(不是我的代码)工厂调用，当使用时，它不会返回 then 属性或任何可用于运行 successCallback 方法的东西(错误本身是 TypeError: Cannot读取未定义的属性 'then')。我不确定可能是什么原因，但调用的许多独特组件可能是原因，例如对 Web 服务的多次嵌套 $http.post 调用。

    updateDocument: function(documentId,  newFileData, appointmentFileName = null, appointmentCategory = null, appointmentId = null) {
        //Get Existing Document Details (including Revision)
        //document.
        documentsService.documentsFactory.getDocumentRecordById(documentId).then(
            function successCallback(response) {
                console.debug("Response", response);

                var NextRevision = parseInt(response.data.revision) + 1;

                if ((appointmentCategory === null) || (appointmentCategory === undefined)) {
                    appointmentCategory = response.data.category_id;
                }

                if ((appointmentId === null) || (appointmentId === undefined)) {
                    var ErrorObj = {
                        status: 10,
                        message: 'Appointment ID not defined.'
                    };
                    return ErrorObj;
                }

                if ((appointmentFileName === null) || (appointmentFileName === undefined)) {
                    appointmentFileName = response.data.filename;
                }

                if ((newFileData === null) || (newFileData === undefined)) {
                    var ErrorObj = {
                        status: 11,
                        message: 'File Data not defined.'
                    };
                    return ErrorObj;
                }

                var action = 'set_document_revision';
                var endpoint = cfg.url;
                var sessionId = systemService.sessionService.getSessionId();

                var DocRevObj = {
                    session: sessionId, 
                    document_revision: {
                        id: documentId,
                        file: newFileData,
                        filename: appointmentFileName,
                        revision: NextRevision                        
                    }
                };

                var DocNodeObj = {
                    session: sessionId,
                    module: "Documents",
                    name_value_list: [{
                        name: 'document_name',
                        value: appointmentFileName
                    }, {
                        name: 'category_id',
                        value: appointmentCategory
                    }, {
                        name: 'id',
                        value: documentId
                    }]                      
                };

                var RevisionRequestParams = {
                    method: action,
                    input_type: "JSON",
                    response_type: "JSON",
                    rest_data: DocRevObj
                };

                var NodeRequestParams = {
                    method: "set_entry",
                    input_type: "JSON",
                    response_type: "JSON",
                    rest_data: DocNodeObj
                }

                var headers = {
                    "Content-Type": "application/json"
                };

                return $http.post(endpoint, RevisionRequestParams, headers).then(
                    function successCallback(response2) {
                        console.debug("Successfully Replaced File", response2);

                        //Re-adjust the File Entry to match new changes
                        //(make a call to set_entry)
                        return $http.post(endpoint, NodeRequestParams, headers).then(
                            function successCallback(response3) {
                                console.debug("Successfully Updated File", response3);
                                return response3;
                            },
                            function errorCallback(response3) {
                                console.debug("Error", response3);
                                return response3
                            }
                        );

                        return response2;
                    },
                    function errorCallback(response2) {
                        console.debug("Error", response2);
                        return response2;
                    }
                ); 
                console.debug("Success", response);
                return response;
            }, function errorCallback(response) {
                console.debug("Error", response);
                return response;
            }
        );
    }

引用方法调用(在 Controller 内，在单击事件时触发)

appointmentsService.appointmentsFactory.updateDocument(CurrentDocumentId, result, NewFileName, NewDocumentType, CurrentAppointmentID).then(
                    function successCallback(response) {
                        //Success Callback Logic                        
                    },
                    function errorCallback(response) {

                    });

事实上，在 Promises 返回任何内容之前，对 updateDocument 的调用是否有可能得到返回？如果是这样，我有哪些解决方案？

Answer 1

您的 updateDocument 函数不返回任何内容。在 getDocumentRecordById 调用之前添加 return。

var updateDocument = function(documentId, newFileData, appointmentFileName = null, appointmentCategory = null, appointmentId = null) {
//Get Existing Document Details (including Revision)
//document.
return documentsService.documentsFactory.getDocumentRecordById(documentId).then( 
...