Return 解决了服务中的 $resource

Question

我是编写服务的新手。我正在我的工厂调用一个调用一系列操作的方法。

1) 从数据库获取数据 2) 等待 $promise resolve 然后比较 & 过滤结果 3) return 新筛选列表

当我注销 $scope.new_list 时，我得到的只是一个空对象。有人可以帮我解决我做错的事吗？

  people.factory('uniqueContacts', ['apiResource', function(apiResource) {
    function getDB() {
         return apiResource.query({api_resource:'people'})
  }
  function generateList(newlistdata){
    getDB().$promise.then(function(result){

           newlist = _.difference(newlistdata, result);
         })
          return new_list;
    });
  }
    return{
      buildList: function(newlistdata){
        return generateList(newlistdata);
      }
    }
  }]);


//in my controller
  $scope.new_list = uniqueContacts.buildList(newlistdata);
  console.log($scope.new_list) // undefined

Answer 1

您的服务功能应该return new_list 成功

getDB().$promise.then(function(result){
       newlist = _.difference(newlistdata, result);
       return new_list;
     })
});

控制器

 uniqueContacts.buildList(newlistdata).then(function(new_list){
   $scope.new_list = new_list;
 });

Answer 2

由于您正在尝试同步输出异步调用，因此它不会输出任何内容。试试这个。

// Factory
people.factory('uniqueContacts', [
  'apiResource',
  function(apiResource) {
    function getDB() {
     return apiResource.query({api_resource:'people'})
    }
    function generateList(newlistdata){
      return getDB().$promise.then(function(result){
        // NOTE: You need to return the data you want the promise to
        //  resolve with.
        return _.difference(newlistdata, result);
      }, function (err) {
        // TODO: Handle error
      ).catch(function (err) {
        // TODO: Handle error that may have happened in the `then`.
        // http://odetocode.com/blogs/scott/archive/2014/04/21/better-error-handling-in-angularjs.aspx
      };
    }
    return {
      // NOTE: There is no need to wrap `generateList` in an anonymous
      //  function when both take the same parameters, you can use the
      //  function definition directly.
      buildList: generateList;
    };
  }
}]);

// Controller
// NOTE: `buildList` returns a promise that is asynchronously 
//  resolved/rejected. So in order to get the data returned you must 
//  use the `then` method.
uniqueContacts.buildList(newlistdata).then(function (list) {
  $scope.newList = list;
  console.log($scope.newList);
});

参考文献：

Answer 3

您应该等待请求的响应（承诺）

function generateList(newlistdata){
    getDB().$promise.then(function(result){
        newlist = _.difference(newlistdata, result);
        return new_list;
    })
});

或者如果你想处理错误：

function generateList(newlistdata){
    getDB().$promise.then(function(result){
        newlist = _.difference(newlistdata, result);
        return new_list;
    }, function(error) {
    // TODO something when error
    })
});

Return 解决了服务中的 $resource

Return resolved $resource within service

angularjs

angularjs-service

angularjs-scope

angular-promise