Angularjs服务是单例吗? [英] Are Angularjs services singleton?

问题描述

在参考中，我读到:

最后，重要的是要意识到所有Angular服务都是 应用单例.这意味着只有一个实例 每个喷油器有特定的服务.

Lastly, it is important to realize that all Angular services are application singletons. This means that there is only one instance of a given service per injector.

但是用这个简单的代码似乎不是单例

but with this simple code seems not to be a singleton

'use strict';
            angular.module('animal', [])
                .factory('Animal',function(){
                    return function(vocalization){
                        return {
                            vocalization:vocalization,
                            vocalize : function () {
                                console.log('vocalize: ' + this.vocalization);
                            }
                        }
                    }
                });    
                angular.module('app', ['animal'])
                    .factory('Dog', function (Animal) {
                        return Animal('bark bark!');
                    })
                    .factory('Cat', function (Animal) {
                        return Animal('meeeooooow');
                    })
                .controller('MainCtrl',function($scope,Cat,Dog){
                     $scope.cat = Cat;
                     $scope.dog = Dog;
                     console.log($scope.cat);
                     console.log($scope.dog);
                    //$scope.cat = Cat;
                });

我有点困惑，你能解释一下这是怎么回事吗?

I'm a little confused can you explain me what's the matter ?

更新1 可能我不是棚子里最犀利的工具 但在@Khanh回复后会更好 参考资料中的解释不是很清楚.

UPDATE 1 May be I'm not the sharpest tool in the shed but afer the @Khanh TO reply it would be a better explanation in the reference it's not very clear.

更新2

'use strict';
            angular.module('animal', [])
                .factory('Animal',function(){
                        return {
                            vocalization:'',
                            vocalize : function () {
                                console.log('vocalize: ' + this.vocalization);
                            }
                        }

                });
                angular.module('dog', ['animal'])
                    .factory('Dog', function (Animal) {
                        Animal.vocalization = 'bark bark!';
                        Animal.color = 'red';
                        return Animal;
                    });

                angular.module('cat', ['animal'])
                   .factory('Cat', function (Animal) {
                        Animal.vocalization = 'meowwww';
                        Animal.color = 'white';
                        return Animal;
                    });
                 angular.module('app', ['dog','cat'])
                .controller('MainCtrl',function($scope,Cat,Dog){
                     $scope.cat = Cat;
                     $scope.dog = Dog;
                     console.log($scope.cat);
                     console.log($scope.dog);
                    //$scope.cat = Cat;
                });

BOOM，这是一个单身人士！

BOOM it's a singleton !

更新3

但是，如果您喜欢

'use strict';
            angular.module('animal', [])
                .factory('Animal',function(){
                    return function(vocalization){
                        return {
                            vocalization:vocalization,
                            vocalize : function () {
                                console.log('vocalize: ' + this.vocalization);
                            }
                        }
                    }
                });    
                angular.module('app', ['animal'])
                    .factory('Dog', function (Animal) {
                        function ngDog(){
                            this.prop = 'my prop 1';
                            this.myMethod = function(){
                                console.log('test 1');
                            }
                        }
                        return angular.extend(Animal('bark bark!'), new ngDog());
                    })
                    .factory('Cat', function (Animal) {
                        function ngCat(){
                            this.prop = 'my prop 2';
                            this.myMethod = function(){
                                console.log('test 2');
                            }
                        }
                        return angular.extend(Animal('meooow'), new ngCat());
                    })
                .controller('MainCtrl',function($scope,Cat,Dog){
                     $scope.cat = Cat;
                     $scope.dog = Dog;
                     console.log($scope.cat);
                     console.log($scope.dog);
                    //$scope.cat = Cat;
                });

有效

推荐答案

这是单例，只有一个对象，但是被注入到许多地方. (对象通过引用传递给方法)

It's singleton, there is only one object, but is injected into many places. (objects are passed by reference to a method)

您所有的Animal都是指向同一动物对象的对象指针，在您的情况下，该动物对象是函数. 您的Cat和Dog是通过此函数构造的对象.

All your Animal are object pointers referring to the same animal object which is a function in your case. Your Cat and Dog are objects constructed by this function.

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