Connecting to MongoDB using Mongoose in multiple files

You need to require Mongoose and open a new connection to it in your server.js so you can access it through different modules.

Suppose you are using both express and body-parser

server.js:

. . .var mongoose   = require('mongoose');var port       = process.env.PORT || 3000;var express    = require('express');var bodyParser = require('body-parser');. . .var app             = express();mongoose.connect("mongodb://localhost/MyApp");. . .app.use(bodyParser.json());. . .require('./app/routes.js')(app);app.listen(port);console.log('App listening on port ' + port);

Then, you can access it easily. Let's suppose you want to set-up a mongoose schema.

mySchema.js:

var mongoose = require('mongoose');var Schema   = mongoose.Schema;var user = new Schema({          name: {type: String, required : true}});module.exports = mongoose.model('user', user);

Or you just want to retrieve all user or save a new user to the user collection, supposing you are passing it an object req which has some properties like name:

user.factory.js

require('mongoose');var User = require('mySchema.js');exports.getUsers = getUsers;exports.postUser = postUser;function getUsers() {  return new Promise( function (resolve, reject) {    var query = User.find({});    query.exec(function(err, users) {        if (err){            return reject({err : 'Error while fetching users'});        }        // If no errors are found, it responds with a JSON of all users        return resolve(users);     });  });}function postUser(req) {    return new Promise( function (resolve, reject) {    // Creates a new User based on the Mongoose schema and the post body      var newUser = new User(req.body);      // New User is saved in the db.      newUser.save(function(err) {          console.log('err',err);          if (err){              return reject({err : 'Error while saving new user'});          }          // If no errors are found, it responds with a JSON of the new users          return resolve(req.body);      });    });}

Also, suppose you want to set-up a route to intercept http requests. For instance, a request to save a new user.

routes.js:

var UserFactory = require('./factories/user.factory.js');// Opens App Routesmodule.exports = function(app) {   /** Getting all the users **/   app.get('/users', function(req, res) {     UserFactory.getUsers().then( function (users) {        res.json(users);     }, function (error) {        res.json(error);     });   });   /** Posting a new geometry **/   app.post('/users', function(req, res) {     UserFactory.postUsers(req).then( function (user) {        return res.json(user);     }, function (error) {        res.json(error);     });   });}

And, on the front-end, the user inserts a user name in a form, then clicks on submit button and you call a createNewUser function:

. . .var createNewUser = function(userName){   var user = {                  name : userName //Goofy   };   console.log(user.name); //Goofy   postNewUser(user).then( function( response, err){     if(err){       console.log('Error while saving new user');     } else {       console.log('User '+response+' successfully saved');     }   });}function postNewUser(user){  return new Promise(function (resolve, reject) {     // Saves user data to the db     $http.post('/users', user)          .success(function(res) {            if(res.error){               return reject(res.error);            }               return resolve(res);     });   });  }

You can also set mongoose globally in your server.js so you don't need to require it in your modules

var mongoose = require('mongoose');. . .global.mongoose = mongoose;

Hope I've been helpful.