对服务与工厂的困惑 [英] Confused about Service vs Factory

问题描述

据我所知，在工厂内部时，我返回一个注入控制器的对象.在服务内部时，我使用 this 处理对象并且不返回任何内容.

As I understand it, when inside a factory I return an object that gets injected into a controller. When inside a service I am dealing with the object using this and not returning anything.

我假设服务总是单例，并且新工厂对象被注入到每个控制器中.然而，事实证明，工厂对象也是单例对象吗?

I was under the assumption that a service was always a singleton, and that a new factory object gets injected in every controller. However, as it turns out, a factory object is a singleton too?

示例代码演示:

var factories = angular.module('app.factories', []);
var app = angular.module('app',  ['ngResource', 'app.factories']);

factories.factory('User', function () {
  return {
    first: 'John',
    last: 'Doe'
  };
});

app.controller('ACtrl', function($scope, User) {
  $scope.user = User;
});

app.controller('BCtrl', function($scope, User) {
  $scope.user = User;
});

当改变ACtrl中的user.first时，结果是BCtrl中的user.first也被改变了，例如User 是单例?

When changing user.first in ACtrl it turns out that user.first in BCtrl is also changed, e.g. User is a singleton?

我的假设是一个新实例被注入到带有工厂的控制器中?

My assumption was that a new instance was injected in a controller with a factory?

推荐答案

所有 Angular 服务都是单例:

文档(参见作为单例的服务):https://docs.angularjs.org/guide/services

最后，重要的是要意识到所有 Angular 服务都是应用程序单例.这意味着每个注入器只有一个给定服务的实例.

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.

服务和工厂的基本区别如下:

Basically the difference between the service and factory is as follows:

app.service('myService', function() {

  // service is just a constructor function
  // that will be called with 'new'

  this.sayHello = function(name) {
     return "Hi " + name + "!";
  };
});

app.factory('myFactory', function() {

  // factory returns an object
  // you can run some code before

  return {
    sayHello : function(name) {
      return "Hi " + name + "!";
    }
  }
});

查看有关 $provide 的演示文稿:http://slides.wesalvaro.com/20121113/#/

Check out this presentation about $provide: http://slides.wesalvaro.com/20121113/#/

这些幻灯片用于 AngularJs 聚会之一:http://blog.angularjs.org/2012/11/more-angularjs-meetup-videos.html

Those slides were used in one of the AngularJs meetups: http://blog.angularjs.org/2012/11/more-angularjs-meetup-videos.html

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