Question

175

Call function of app.js from within module in node.js?

rated 0 times [ 179] [ 4] / answers: 1 / hits: 20273 / 13 Years ago, fri, january 27, 2012, 12:00:00

Let's say I have the following app.js (obviously very simplified):

var express = require('express'),

    app = express.createServer();



// include routes

require('./lib/routes')(app);



// some random function

var foo = function() {

    return 'bar';

};



// another random function

var foo2 = function() {

    return 'bar2';

};

And then I have the routes module:

module.exports = function(app){

    app.get('/some/route', function(req, res){

        var fooBar = foo(),

            fooBar2 = foo2();



        res.end(fooBar + fooBar2);

    });

};

This obviously doesn't work since foo and foo2 weren't defined within the module. Is there a way to make this work, or at least a different pattern to better accomplish what this?

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naya

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3 Years ago

answered 13 Years ago dayanaracolleeng · Accepted Answer

Well you can just put these two functions in an object and pass them on the initialization of the routes.js .

var express = require('express'),

    app = express.createServer();



// some random function

var foo = function() {

    return 'bar';

};



// another random function

var foo2 = function() {

    return 'bar2';

};



var fns = {foo : foo, foo2: foo2}



// include routes

require('./lib/routes')(app, fns);

in routes:

module.exports = function(app, fns){

    app.get('/some/route', function(req, res){

        var fooBar = fns.foo(),

            fooBar2 = fns.foo2();



        res.end(fooBar + fooBar2);

    });

};

This is how would I do it. You can also include them in the app object. Beside passing them in init functions, you can also export those two functions and require them in routes.js.

var express = require('express'),

    app = express.createServer();



// some random function

var foo = function() {

    return 'bar';

};



// another random function

var foo2 = function() {

    return 'bar2';

};



module.exports = {foo : foo, foo2: foo2}



// include routes

require('./lib/routes')(app, fns);

in routes:

module.exports = function(app){

    var fns = require('../app.js');

    app.get('/some/route', function(req, res){

        var fooBar = fns.foo(),

            fooBar2 = fns.foo2();



        res.end(fooBar + fooBar2);

    });

};

But I don't like the idea of it, since it makes circular dependencies. Don't have any good feelings about them.