如何使用$ lookup在流星中聚合

Question

我有两个收藏。 Main_Category或Sub_Category。我想在流星中聚合

//Main_Category document
{
   "_id" : "Jqcmc9sMHHN3qpJB7",
   "name" : "ahskdhkj",
   "icon_image" : "nbdenck",
   "description" : "jksdfhkj"
}


//Sub_Category document
{
  "_id" : "smjySSxboeGpY8Drn",
  "name" : "sub1",       
  "icon_image" : "nbdenck",
  "main_category_id" : "Jqcmc9sMHHN3qpJB7"
 }



var pipeline = [{
        $lookup: {
            from: "Sub_Category",
            localField: "_id",
            foreignField: "main_category_id",
            as: "subcategory"
        }
    }];
    var data = Main_Category.aggregate(pipeline)

我也尝试使用meteorhacks：聚合包。错误消息是 错误：异常：无法识别的管道阶段名称：'$ lookup'

   var pipeline = [{
        $lookup: {
            from: "Sub_Category",
            localField: "_id",
            foreignField: "main_category_id",
            as: "subcategory"
        }
    }];
    var data = Main_Category.aggregate(pipeline)