AngularJS 承诺未定义

Question

我已经阅读了网络上的几个示例和 SO 上的问题，但我仍然缺少一些东西。

我有一项服务可以从我的 API 中获取订单数据。我想解决服务内部的承诺。服务内的 console.log 记录了正确的数据。

但是，在我的控制器中，我得到 "TypeError: Cannot read property 'then' of undefined"

我以为控制器函数会等待数据解析？

服务

angular.module('app')
.factory('orderService', function($http) {

    // DECLARATIONS
    var baseUrl = 'http://api.example.com/';
    var method = 'GET';
    var orderData = null;

    return {
        getOrderData: getOrderData
    };

    // IMPLEMENTATIONS
    function getOrderData(ordernumber) {        
        // order data does not yet exist in service
        if(!orderData) {
            dataPromise = $http({
                url: baseUrl + 'order/' + ordernumber,
                method: method,
                withCredentials: true,
                headers: {
                    'Content-Type': 'application/json'
                }
            // success
            }).then(function(response) {
                orderData = response.data;
                console.log('Received data: ' + JSON.stringify(response.data));
                return orderData;               
            },
            // faliure
            function(error) {
                  console.log("The request failed: " + error);
            });
        // order data exist in service
        } else {
            console.log('Data present in service: ' + orderData);
            return orderData;
        }
    } // end: getOrderData function
}); // end: customerService

控制器

app.controller('orderController', function($scope, $stateParams, orderService) {

   $scope.ordernumber = $stateParams.order;

   orderService.getOrderData($scope.ordernumber)
    // success 
    .then(function(response) {
        $scope.order = response;
        console.log('Controller response: ' + response);
    },
    // faliure
    function(error) {
      console.log("The request failed: " + error);
    });
});

Answer 1

你的函数 getOrderData 没有返回一个承诺

function getOrderData(ordernumber) {        
   var deferred = $q.defer();
        // order data does not yet exist in service
        if(!orderData) {
            dataPromise = $http({
                url: baseUrl + 'order/' + ordernumber,
                method: method,
                withCredentials: true,
                headers: {
                    'Content-Type': 'application/json'
                }
            // success
            }).then(function(response) {
                orderData = response.data;
                console.log('Received data: ' + 
                 JSON.stringify(response.data));
                deferred.resolve(orderData);               
            },
            // faliure
            function(error) {
              deferred.reject(error);
                  console.log("The request failed: " + error);
            });
        // order data exist in service
        } else {
            console.log('Data present in service: ' + orderData);
            deferred.resolve(orderData);
        }
    else {
     deferred.reject('Not set!');
   }

return deferred.promise;
    } // end: getOrderData function