Node.js require connection inside multiple module












2














I have a question about the require function of Node.js, imagine we have a module that manages the connection, and many small modules that contain the routes.



An example of connection file: db.js



const mysql = require('mysql');



const connection = mysql.createConnection({

 host     : '127.0.0.1',

 user     : 'root',

 password : '',

 database : 'chat'

});



connection.connect(function(err) {

 if (err) throw err;

});



module.exports = connection;


and one of the various files to manage the routes:



const app = express();

const router = express.Router();

const db = require('./db');



router.get('/save',function(req,res){

 // some code for db

});



module.exports = router;


Imagine now to have 20 routes with the same require. How will node.js behave? How many times will my connection be created?






javascript node.js







share|improve this question






















  • Good question. See: stackoverflow.com/questions/30356148/…
    – lependu
    Nov 19 '18 at 15:46
















2














I have a question about the require function of Node.js, imagine we have a module that manages the connection, and many small modules that contain the routes.



An example of connection file: db.js



const mysql = require('mysql');



const connection = mysql.createConnection({

 host     : '127.0.0.1',

 user     : 'root',

 password : '',

 database : 'chat'

});



connection.connect(function(err) {

 if (err) throw err;

});



module.exports = connection;


and one of the various files to manage the routes:



const app = express();

const router = express.Router();

const db = require('./db');



router.get('/save',function(req,res){

 // some code for db

});



module.exports = router;


Imagine now to have 20 routes with the same require. How will node.js behave? How many times will my connection be created?






javascript node.js







share|improve this question






















  • Good question. See: stackoverflow.com/questions/30356148/…
    – lependu
    Nov 19 '18 at 15:46














2












2








2







I have a question about the require function of Node.js, imagine we have a module that manages the connection, and many small modules that contain the routes.



An example of connection file: db.js



const mysql = require('mysql');



const connection = mysql.createConnection({

 host     : '127.0.0.1',

 user     : 'root',

 password : '',

 database : 'chat'

});



connection.connect(function(err) {

 if (err) throw err;

});



module.exports = connection;


and one of the various files to manage the routes:



const app = express();

const router = express.Router();

const db = require('./db');



router.get('/save',function(req,res){

 // some code for db

});



module.exports = router;


Imagine now to have 20 routes with the same require. How will node.js behave? How many times will my connection be created?






javascript node.js







share|improve this question













I have a question about the require function of Node.js, imagine we have a module that manages the connection, and many small modules that contain the routes.



An example of connection file: db.js



const mysql = require('mysql');



const connection = mysql.createConnection({

 host     : '127.0.0.1',

 user     : 'root',

 password : '',

 database : 'chat'

});



connection.connect(function(err) {

 if (err) throw err;

});



module.exports = connection;


and one of the various files to manage the routes:



const app = express();

const router = express.Router();

const db = require('./db');



router.get('/save',function(req,res){

 // some code for db

});



module.exports = router;


Imagine now to have 20 routes with the same require. How will node.js behave? How many times will my connection be created?






javascript node.js




javascript node.js






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 19 '18 at 15:36









Eugenio

153




153












  • Good question. See: stackoverflow.com/questions/30356148/…
    – lependu
    Nov 19 '18 at 15:46


















  • Good question. See: stackoverflow.com/questions/30356148/…
    – lependu
    Nov 19 '18 at 15:46
















Good question. See: stackoverflow.com/questions/30356148/…
– lependu
Nov 19 '18 at 15:46




Good question. See: stackoverflow.com/questions/30356148/…
– lependu
Nov 19 '18 at 15:46












1 Answer
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How many times will my connection be created?




There will be one connection, because "db.js" runs only once. The things you export get stored (module.exports) and that gets returned by every require("./db"). To verify:



 require("./db") === require("./db") // true





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    1 Answer
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    1 Answer
    1






    active

    oldest

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    active

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    active

    oldest

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    1















    How many times will my connection be created?




    There will be one connection, because "db.js" runs only once. The things you export get stored (module.exports) and that gets returned by every require("./db"). To verify:



     require("./db") === require("./db") // true





    share|improve this answer


























      1















      How many times will my connection be created?




      There will be one connection, because "db.js" runs only once. The things you export get stored (module.exports) and that gets returned by every require("./db"). To verify:



       require("./db") === require("./db") // true





      share|improve this answer
























        1












        1








        1







        How many times will my connection be created?




        There will be one connection, because "db.js" runs only once. The things you export get stored (module.exports) and that gets returned by every require("./db"). To verify:



         require("./db") === require("./db") // true





        share|improve this answer













        How many times will my connection be created?




        There will be one connection, because "db.js" runs only once. The things you export get stored (module.exports) and that gets returned by every require("./db"). To verify:



         require("./db") === require("./db") // true






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 19 '18 at 16:10









        Jonas Wilms

        55.7k42750




        55.7k42750






























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