Express & splitting routes into separate files

Question

I have an express app that follows the standard Express 4 format. ie, dependencies at the top, then app config, then routes, and finally, listen.

I'm trying to seperate out my routes into categorised files (eg. routes/authentication.js) however the app isn't carrying through the dependencies so when I run node app.js the app breaks because the CLI says that passport isn't defined in routes/authentication.js, which it isn't, because it's defined at the top of app.js with all the other dependencies.

I guess my question is how can I go about 'sharing' the dependencies so I don't have to list them at the top of every file? This is how i'm requiring the separate files:

app.js

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

routes/authentication.js

module.exports = function (app) {
    [routes]
}

Answer 1

Where a dependency module is really used often where you already have access to app, you can set the value on app, eg app.config = require('./config') . ( However , where it is generally best to specify the dependencies for a particular module at the top of that module for the sake of clarity. There's no harm other than adding a bit more code for each module.)

Additionally, although it is fine to use a constructor function and passing in app to this function, you could also use modules for this purpose. Ensure you export app the moment you create it, ie var app = module.exports = express(); and then just var app = require('../app'); from other libraries. You'll see this in some of the Express examples.