服务功能内的角度呼叫服务功能，对此不起作用

Question

我试图在同一服务的另一个功能内调用服务功能，但看到一些奇怪的行为。希望这是我忽略的一些明显的错误。这里是我服务的相关部分：

app.factory('Data', ['$http', function($http) { 

     var Data = this; 
     var theProduct = {}; 
     var seletedSku = {}; 
     var uniqueItem = {}; 

     return { 

       product: function(){ 
         return theProduct; 
       }, 

       getProduct: function(ext_id){ 

         console.log(Data.product); 
         console.log(this.product); 

       }, 
     } 
}]); 

正如你所看到的，getProduct()函数中，我只是试图登录该product功能只是为了确认参考正常工作。当getProduct()被调用时，第一线记录undefined，第二行记录了我所期望的，product功能：

function(){ 
    return theProduct; 
} 

为什么不工作我参考？您可以看到服务的顶部，我节省了this到Data变量。有任何想法吗？

我下面粘贴仅供参考，全程服务代码的情况下，它可以帮助：

app.factory('Data', ['$http', function($http) { 

    var Data = this; 
    var theProduct = {}; 
    var seletedSku = {}; 
    var uniqueItem = {}; 

    return { 
     //return the current product being used in the app 
     product: function(){ 
      return theProduct; 
     }, 

     //get a products data from the server and set it as the current product being used by the app 
     getProduct: function(ext_id){ 

      console.log(Data.product); 
      console.log(this.product); 

      return $http.post('get_product', {product_id: ext_id}).success(function(data){ 
       theProduct = data; 

       //when a product is fetched, set the app's unique item 
       if(theProduct.unique_item){ 
        Data.setUniqueItem(theProduct.unique_item); 
       } 
       else{ 
        Data.setUniqueItem({}); 
       } 
      }); 

     }, 

     //change the currently selected sku for the app 
     setSku: function(sku){ 

      if(sku){ 
       selectedSku = sku; 
      } 
      else{ 
       //null was passed, meaning, the -- Selected SKU -- option 
       //was chosen, so reset selectedSku back to an empty object 
       selectedSku = {}; 
      } 

      //when sku is set, also need to set current unique item 
      if(selectedSku.unique_item){ 
       Data.setUniqueItem(selectedSku.unique_item); 
      } 
      else{ 
       Data.setUniqueItem({}); 
      } 

      return selectedSku; 
     }, 

     //get the currently selected sku for the app 
     sku: function(){ 
      return selectedSku; 
     }, 

     //set the current unique item 
     setUniqueItem: function(item){ 

      //before set a unique item, we need to check if the unique 
      //item we are setting is the same as the current unique item. 
      //if it is, we need to set them equal so the new item reflects 
      //current state of it since it's not repulling the item from the database 
      if(item.id != uniqueItem.id){ 
       //only change the unique item if they are not the same 
       //if they are the same, just leave unique item as is 
       uniqueItem = item; 
      } 
      console.log(uniqueItem); 
      return uniqueItem; 
     }, 

     //get the current unque item 
     uniqueItem: function(){ 
      return uniqueItem; 
     } 
    } 
}]); 

Answer 1

因为在参考时，this没有上下文本身作为对象常量。