nodejs+mongodb aggregate级联查询操作示例

var AountSchema = new Schema({
  loginname: {type: String},
  password: {type: String},
  /
    联系方式
   /
  //账户公司名
  Name: {type: String},
  //地址
  address: {type: String},
  //公司介绍
  intro: {type: String}
});
mongoose.model('Aount', AountSchema);

var CustomerSchema = new Schema({
  /
    基本信息
   /
  //密码
  password: {type: String},
  //归属于哪个Aount
  belongToAount: {type: ObjectId, ref: 'Aount'},
  //手机号，登录用
  mobile: {type: String},
  //真实姓名
  realname: {type: String}
});
CustomerSchema.index({belongToAount: 1, mobile: 1}, {unique: true});
mongoose.model('Customer', CustomerSchema);

var articleSchema= new Schema({
  belongToAount: {type: ObjectId, ref: 'Aount'},
  title: {type: String},
  text: {type: String},
  createTime: {type: Date, default: Date.now},
  author: {type: ObjectId, ref: 'Customer'},
  //0,待确认,1 有效 ,-1 无效
  status: {type: Number, default: 0}
});
articleSchema.index({belongToAount: 1, createTime:-1,author: 1}, {unique: false});
mongoose.model('article', articleSchema);

exports.getRankList = function (aountid, callback) {
  AticleModel.aggregate(
    {$match: {belongToAount: mongoose.Types.ObjectId(aountid), status: 1}},
    {$group: {_id: {customerId: "$author"}, number: {$sum: 1}}},
    {$sort: {number: -1}}).limit(10).exec(function (err, aggregateResult) {
    if(err){
      callback(err);
      return;
    }
      var ep = new EventProxy();
      ep.after('got_customer', aggregateResult.length, function (customerList) {
        callback(null, customerList);
      });
       aggregateResult.forEach(function (item) {
        Customer.findOne({_id: item._id.customerId}, ep.done(function (customer) {
          item.customerName = customer.realname;
          item.customerMobile=cusomer.mobile;
          // do someting
          ep.emit('got_customer', item);
        }));
      })
    });
};

[ { _id: { customerId: 559a5b6f51a446602032fs21 }, number: 5,
customerName: 'test2',
mobile:22 } ，
{ _id: { customerId: 559a5b6f51a446602041ee6f }, number: 1,
customerName: 'test1',
mobile: 11 } ]