无法读取未定义 AngularJS 的属性“then”

Question

我写了一个工厂方法：

myApp.factory('GetUserCurrentLocationService', ['$q', function ($q) {
            var GetUserCurrentLocationService = {};
            GetUserCurrentLocationService.getLocation = function () {
                var def = $q.defer();
                if (navigator.geolocation) {
                    navigator.geolocation.getCurrentPosition(function (position) {
                        def.resolve(position);
                        return def.promise;
                    });
                }
            }
            return GetUserCurrentLocationService;
        }
    ]);

在控制器中我写过：

GetUserCurrentLocationService.getLocation().then(function(response){
        console.log(response);
    },function(error){
        console.log(error);
    })

但是每当我运行它时，我都会收到错误 Cannot read property 'then' of undefined AngularJS

Answer 1

到目前为止，您的工厂 getLocation 函数返回 undefined，它没有返回 Promise，因此该错误是预期的。基本上你放错了return def.promise; 声明。

GetUserCurrentLocationService.getLocation = function () {
    var def = $q.defer();
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(function (position) {
            def.resolve(position);
        });         
    } else {
        //Also reject if navigator.geolocation is undefined
        def.reject({});
    }
    //Function should return promised
    return def.promise;
}