AngularJS - 比较资源和对象(AngularJS - Comparing resources and objects)

 在Angular中，一些方法调用返回Objects ，一些方法返回Resources ，这使得它们难以比较。 我有一个用户模型和一个权限模型。 用户模型定义为： 
 
myApp.service('User', function($resource) {
  var User = $resource('users/:userId.json');
  return User;
});
 
 并定义了权限模型： 
 
myApp.service('Permission', function($resource) {
  var Permission = $resource('permissions');
  return Permission;
});
 
 当我检索用户时，返回的json具有用户的权限： 
 
{"id":1,"username":"Admin","group_id":"1","permissions":[{"id":1,"name":"Create Users"},"id":2,"name":"Delete Users"}]}
 
 这意味着当我检索用户时，我可以使用.permissions访问他/她的权限。例如 
 
User.get({userId: 1}).permissions
 
 我想将其与所有权限列表进行比较，并获取用户尚未拥有的权限列表： 
 
$scope.user = User.get({userId: 1});
Permission.query().$promise.then(function(all){
  $scope.user.$promise.then(function(u){
    $scope.unselected_permissions = _.difference(all, u.permissions);
  });
});
 
 问题是， all都是一个资源数组，而u.permissions是一个对象数组。 是否有一种简单的方法可以让u.permissions返回资源列表？ 是否有更简单的事情可以做而不是等待承诺在这里解决？ 

In Angular, some method calls return Objects, and some return Resources, which make them difficult to compare. I have a user model and a permission model. The user model is defined:
 
myApp.service('User', function($resource) {
  var User = $resource('users/:userId.json');
  return User;
});
 
And the permission model is defined:
 
myApp.service('Permission', function($resource) {
  var Permission = $resource('permissions');
  return Permission;
});
 
When I retrieve a user, the json returned has the user's permissions:
 
{"id":1,"username":"Admin","group_id":"1","permissions":[{"id":1,"name":"Create Users"},"id":2,"name":"Delete Users"}]}
 
This means when I retrieve a user, I can access his/her permissions with .permissions For example
 
User.get({userId: 1}).permissions
 
I want to compare this with the list of all permissions, and get a list of the permissions that the user does not already have:
 
$scope.user = User.get({userId: 1});
Permission.query().$promise.then(function(all){
  $scope.user.$promise.then(function(u){
    $scope.unselected_permissions = _.difference(all, u.permissions);
  });
});
 
The problem is, all is an array of Resources, and u.permissions is an array of Objects. Is there a simple way to get u.permissions to return a list of resources? Is there something simpler I can do instead of waiting for the promises to resolve here?

原文：https://stackoverflow.com/questions/24789080