Simple Multi-tenancy for MongoDB

modej.js

var tenancy = require('../utils/tenancy');

function shiftsModel(mongo) {

	function create(user, shift, callback) {
		mongo.shifts.save(tenancy(user, shift), tenancy(callback));
	}

	function getByWeek(user, week, callback) {
		mongo.shifts.find(tenancy(user, {week: +week}), tenancy(callback));
	}

	function getByWeekByDay(user, week, day, callback) {
		mongo.shifts.findOne(tenancy(user, {week: +week, day: +day}), tenancy(callback));
	}

	return {
		create: create,
		getByWeek: getByWeek,
		getByWeekByDay: getByWeekByDay
	};
}

module.exports = shiftsModel;

tenancy.js

var util = require('util');
var _ = require('underscore');

function removeTenant(result) {
	return _.omit(result, 'user');
}

function wrapCallback(callback) {
	return function (err, results) {
		if (err) {
			return callback(err);
		}

		return util.isArray(results) ? callback(null, results.map(removeTenant)) : callback(null, removeTenant(results));
	};
}

function tenancy(user, data) {
	if (typeof user === 'function') {
		return wrapCallback(user);
	}

	return _.extend(data, {user: _.pick(user, ['id', 'firstname', 'lastname', 'email'])});
}

module.exports = tenancy;