Correct way to search for MongoDB entries by '_id' in Node

You need to require the ObjectId function before using it:

var ObjectId = require('mongodb').ObjectID;

If you are using MongoJS, you can do:

var ObjectId = mongojs.ObjectId;

Then,

db.users.find({"_id": ObjectId(id)}, function(err, user){...}

if you are using mongoose you can try this:

var mongoose = require('mongoose')
usersSchema = mongoose.model('users'),
mongoose.Types.ObjectId("<object_id>")

usersSchema.find({"_id": mongoose.Types.ObjectId("<object_id>")}, function (err, record) {
// Do stuff
});