node.js - ExpressJS mongodb 多个查询

Question

我想获取两个集合的数据。如何在一个响应中发送这些数据？

这是我的代码:

    //RETURN SINGLE QUERYE
exports.findById = function(req, res) {
    //Get Params
    var querye_id =new BSON.ObjectID(req.params.id); 
    var querye;

    //Get Single Querye
    db.collection('queryes', function(err, collection) {
        collection.findOne({'_id':querye_id}, function(err, item) {
            querye=item;
        });

    });
    //Get Questions and Answers
    db.collection('questions', function(err, collection) {
        collection.find().toArray(function(err, items) {
            querye.questions=items;
        });
    });

    //Send Response
     res.send(querye);

};

我有 undefined variable 查询。如何解决？

Answer 1

var async = require('async');

function getQueries(id, callback) {
  db.collection('queryes', function(err, collection) {
    collection.findOne({'_id':id}, callback);
  });
}

function getQuestions(callback) {
  db.collection('questions', function(err, collection) {
    collection.find().toArray(callback);
  });
}

exports.findById = function(req, res) {
  var querye_id =new BSON.ObjectID(req.params.id);
  async.parallel({
    querye: async.apply(getQueries, query_id),
    questions: getQuestions
  }, function (error, results) {
    if (error) {
      res.status(500).send(error);
      return;
    }
    results.querye.questions = results.questions;
    res.send(results.querye);
  });
};