How to rename/alias field(s) while fetching it from MongoDB through query using MongoDB-Node.JS native drive?

mongodb, mongodb-query, node.js

Solution

Use aggregate framework of MonogDB (But you need to upgrade the MongoDB server instance to >= 2.1).

The following is the soultion for the above example

var Db = require('mongodb').Db,
    MongoClient = require('mongodb').MongoClient,
    Server = require('mongodb').Server,
    ReplSetServers = require('mongodb').ReplSetServers,
    ObjectID = require('mongodb').ObjectID,
    Binary = require('mongodb').Binary,
    GridStore = require('mongodb').GridStore,
    Code = require('mongodb').Code,
    BSON = require('mongodb').pure().BSON,
    assert = require('assert');
db.open(function (err, db) {
    if (err) console.dir(err);
    db.createCollection('simple_limit_skip_find_one_query', function (err, collection) {
        if (err) console.dir(err);

        collection.insert([{ a: 1, b: 1 }, { a: 2, b: 2 }, { a: 3, b: 3}], { w: 1 }, function (err, doc) {
            if (err) console.dir(err);

            collection.aggregate([
            { $project: {
                a: 1,
                _id:0,
                baseID: "$b"
            }
            }
          ], function (err, doc) {
              if (err) console.dir(err);
              console.log(doc);
          });
        });
    });
});

Output:

[ { a: 1, baseID: 1 },
  { a: 2, baseID: 2 },
  { a: 3, baseID: 3 }]

Problem

Consider the following code, which I am using to fetch the data from my local MongoDB server. ``` var Db = require('mongodb').Db, MongoClient = require('mongodb').MongoClient, Server = require('mongodb').Server, ReplSetServers = require('mongodb').ReplSetServers, ObjectID = require('mongodb').ObjectID, Binary = require('mongodb').Binary, GridStore = require('mongodb').GridStore, Code = require('mongodb').Code, BSON = require('mongodb').pure().BSON, assert = require('assert'); var db = new Db('test', new Server('localhost', 27017)); db.open(function(err, db) { db.createCollection('simple_limit_skip_find_one_query', function(err, collection) { assert.equal(null, err); collection.insert([{a:1, b:1}, {a:2, b:2}, {a:3, b:3}], {w:1}, function(err, result) { assert.equal(null, err); collection.findOne({a:1}, {fields:{b:1}}, function(err, doc) { // I got the read document in the object 'doc' }); }); }); }); ``` Now, I want to rename a field name while retrieving only (not in the DB), for example with the above code, I have a field named `b` in the returned object `doc` I want it to be `baseID` instead of `b` Is there any way to do it? Note: I cannot take action on the retrieved object `doc` to rename field like JSON key renaming. I want it to be queried and MongoDB will the same.

Original source