dbtest.js

const mongoose = require('mongoose');
const express = require('express');
const faker = require('faker');

var app = express();

var userSchema = new mongoose.Schema({
    email: {
        type: String,
        required: true,
        unique: true
    },
    name: {
        type: String
    }
}, {
    timestamps: true
});

var bookSchema = new mongoose.Schema({
    name: {
        type: String,
        required: true,
        unique: true
    },
    category: String,
    stock: Number,
    _users: [{
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User'
    }]
}, {
    timestamps: true
});

var User = mongoose.model('User', userSchema);
var Book = mongoose.model('Book', bookSchema);

app.get('/users', function (req, res, next) {
    User.find(function (err, users) {
        if (err)
            next(err);
        else
            res.json(users);
    });
});

app.get('/users/new', function (req, res, next) {
    var obj = {
        name: faker.name.findName(),
        email: faker.internet.email()
    };
    User.create(obj, function (err, user) {
        if (err)
            next(err);
        else
            res.json(user);
    });
});

app.get('/books', function (req, res, next) {
    Book.find(function (err, books) {
        if (err)
            next(err);
        else
            res.json(books);
    });
});

app.get('/books/new', function (req, res, next) {
    var obj = {
        name: faker.name.title(),
        category: faker.random.word(),
        stock: parseInt(Math.random() * 10 + 1),
        _users: []
    };
    Book.create(obj, function (err, book) {
        if (err)
            next(err);
        else
            res.json(book);
    });
});

app.get('/books/:bookId', function (req, res, next) {
    let books = [];
    Book.find(function (err, collection) {
        if (err) next(err);
        else {
            books = collection;
            if (req.params.bookId >= books.length) {
                res.send('There\'s no such book...');
            } else res.json(books[req.params.bookId]);
        }
    });
});

app.get('/books/:bookId/newUser', function (req, res, next) {
    let users = [];
    User.find().lean().distinct('name', function (err, names) {
        if (err) next(err);
        else {
            users = names;
            res.json(users);
        }
    });
})

mongoose.connect('mongodb://localhost:27017/sample', function (err) {

    if (err) throw err;

    app.listen(8080, function () {
        console.log('Listen started');
    });
});