Question

我正在MongoDB上执行聚合查询。结果将作为[object Object]返回。我无法弄清楚如何返回单个结果集。如果我执行result.forEach循环，它会根据我的期望输出正确的个人计数。

架构：

var logbookSchema = new Schema({
id: String,
uid: String,
lid: { type: String, unique: true},
time : { type : Date, default: Date.now },
callsign: String,
contact: String,
start: String,
end: String,
frequency: String,
band: String,
mode: String,
RSTsent: String,
RSTrec: String,
notes: String
})

聚合功能：

Logbook = require("../models/logbook");

    module.exports = function(user_id){
    var today = new Date();
    var todayMinus1Week = new Date();
    todayMinus1Week = todayMinus1Week.setDate(todayMinus1Week.getDate() - 7);
    console.log(today + " | " + todayMinus1Week)
    Logbook.aggregate(
        [
            { "$match": {
                "time": { 
                    "$gte": new Date(todayMinus1Week),"$lt": new Date(today)
                },
                "uid": user_id
            }},
            { "$sort": {
                time: -1
            }},
            { "$group": {
                "_id": { 
                    "day":   { "$dayOfMonth": "$time" },
                    "month": { "$month": "$time"}
                },
                "count": { "$sum": 1 }
            }}
        ],
        function(err,result) {
            if(err){
                console.log("Error:"+err);
            }else{
                console.log("Result ["+user_id+"]:"+result);
                return result;
                //result.forEach(function(entry){
                    //entries.push(entry);;
                //});
            }

        }
    );

};

路由器：

router.get('/dashboard', isAuthenticated, function(req, res, next) {
    Logbook.find({ 'uid' :  req.user.uid }, {}, { limit: 10}, function(err, logbook){
        if (err) { console.log(err); return next(); }
        var Entries = new LogbookData(req.user.uid);
        res.render('dashboard', { 
            user: req.user,
            logbook: logbook,
            locals: {
               firstName: req.session.firstName,
               email: req.session.email,
               admin: req.session.admin
            },
            title: 'QRZLog Dashboard v1.0',
            recentEntries: Entries
        });
    });
});

Answer 1

您的LogbookData函数需要转换为异步函数，因为它依赖于异步函数本身。您不能从异步函数返回值;相反，你需要在函数完成时调用一个continuation函数。

要进行重组，您的代码应该与此类似：

// aggregate function; notice how it takes a callback function.
module.exports = function(user_id, callback) {
  ...
  Logbook.aggregate(..., function(err,result) {
    if (err) {
      console.log("Error:", err);
      return callback(err);
    } else {
      // FWIW, the following line fixes your `[object Object]` issue.
      console.log("Result ["+user_id+"]: %j", result);
      return callback(null, result);
    }
  }
};

// router
router.get('/dashboard', isAuthenticated, function(req, res, next) {
  Logbook.find({ 'uid' :  req.user.uid }, {}, { limit: 10}, function(err, logbook) {
    // XXX: passing `err` with `next()` for proper error handling.
    if (err) { console.log(err); return next(err); }
    // XXX: no need to use `new` here.
    LogbookData(req.user.uid, function(err, entries) {
      if (err) { console.log(err); return next(err); }
      res.render('dashboard', { 
        user: req.user,
        logbook: logbook,
        locals: {
          firstName: req.session.firstName,
          email: req.session.email,
          admin: req.session.admin
        },
        title: 'QRZLog Dashboard v1.0',
        recentEntries: entries
      });
    });
  });
});

MongoDB聚合结果[对象对象]

1 个答案: