How does controllers find models Schema file in mongoose?

Question

I have below structure and I think this is not correct

models/db.js

var mongoose  = require( 'mongoose' );
var mongoURI = 'mongodb://localhost/loc8r';
var mongoDB = mongoose.createConnection(mongoURI);
require('./user');

models/user.js

var mongoose  = require( 'mongoose' );
var Schema =  mongoose.Schema;
var userSchema = new Schema({
    username : { type: String; required: true},
    createdOn: {type: Date, "default": Date.now}
});
mongoose.model('User', userSchema);

controllers/user.js

var mongoose  = require( 'mongoose' );
var user = mongoose.model('User');

My questions are ( co related )

• How does controllers/users.js pages get in touch with models/users.js

• What if there is more than one file in models folder, say model/college.js then Do we add more require() lines in db.js?

• somewhere I see that module.exports are written at the end of the model schema files, does that is right way or above one is correct?

• Why do we keep adding require mongoose continuously in each page? coming from PHP background , I think that once we add require it will be added in child pages when we include the file. is it not so?

Answer 1

Found the more elegant way which re utilize mongoose object across other model files. I hope this will help newbie which are also facing issue to understand the concept.

use module.exports in main db file which is added in require() in app.js

models/db.js

let mongoose  = require('mongoose');
let mongoURI = 'mongodb://localhost/loc8r';    
module.exports = mongoose.connect(mongoURI,options);    
let conn = mongoose.connection;

Note: I have removed require(..other model file ..) from bottom of db.js

---

models/user.js

let mongoose  = require( './db' );
let Schema =  mongoose.Schema;
let userSchema = new Schema({
    username: {type: String; required: true},
    createdOn: {type: Date, "default": Date.now}
});
module.exports = mongoose.model('User', userSchema);

Note: add require('./db') in place of mongoose in each other model file and export the schema using module.exports in bottom

---

controllers/user.js

let User = require('../models/user');

module.exports.userSignup = function(req,res,next) {
    if (req.method == 'POST') {
        var user = new User({
            username: req.body.username,
            password: req.body.password,
            email: req.body.email
        });
        user.save( (err, user) => {
            if(err) return res.status(500).send(err);
            return res.status(200).json(user);
        });
    } 
};

Note: add model files with help of require(...) , so that it will get schema detail and use that variable to save/update new data

feel free to correct if I am wrong or doing the lengthy way.