nodejs access main script context - node.js

Question

Diving into node, I have a question on how an included script, can access the main's script methods or variables
For instance, say that I have a logger object initiated in the main script and I include another js file, which needs access to the logger. How can I do that, without injecting the logger to the included script.
//main node script
var logger = require('logger'),
app = require("./app.js")
//app.js
function something(){
//access logger here !!!!!!!
}
exports.something = something
Hope it is clear
Thanks

Answer 1

Try doing:
//main node script
var logger = require('logger'),
app = require("./app.js")(logger);
//app.js
var something = function (logger){
logger.log('Im here!');
}
module.exports = exports = something;
Edit:
If you want to split your main app's code into different files, on your main script file you can do something like: (This is how I'm splitting my main app.js into different sections)
// main app.js
express = require('express');
...
/* Routes ---------------------*/
require('./config/routes')(app);
/* Socket IO init -------------*/
require('./app/controllers/socket.io')(io);
/* Your other file ------------*/
require('./path/to/file')(app);
...
// config/routes.js
module.exports = function(app){
app.configure(function(){
app.get('/', ...);
...
}
}
// app/controllers/socket.io.js
module.exports = function(io){
// My custom socket IO implementation here
}
// ...etc
Edit 2:
Your function can also return a JS object, in case you want to do something on the main app.js with a custom script.
Example:
// main app.js
...
/* Some controller ---------------------*/
var myThing = require('./some/controller')(app);
myThing.myFunction2('lorem'); // will print 'lorem' on console
...
// some/controller.js
// Your function can also return a JS object, in case you want to do something on the main app.js with this require
var helperModule = require('helperModule');
module.exports = function(app){
var myFunction = function(){ console.log('lorem'); }
// An example to export a different function based on something
if (app.something == helperModule.something){
myFunction = function() { console.log('dolor'); }
}
return {
myFunction: myFunction,
myFunction2: function(something){
console.log(something);
}
}
}
You can also simply export a function or an object containing functions, without sending any parameter like this:
// main app.js
...
var myModule = require('./path/to/module');
myModule.myFunction('lorem'); // will print "lorem" in console
...
// path/to/module.js
module.exports = {
myFunction: function(message){ console.log(message); },
myFunction2: ...
}
Basically, whatever you put inside module.exports is what gets returned after the require() function.

Answer 2

module.exports is what is returned when you require the file. in #DavidOliveros example, that's a function that takes app or io as parameters. the function is executed right after the require takes place.
If you want to expose a method of the included script to the main, try this:
// child.js
module.exports = function(app){
var child = {};
child.crazyFunction = function(callback){
app.explode(function(){
callback();
});
};
child.otherFunction = function(){};
return child;
};
// app.js
var express = require('express');
var app = module.exports = express();
var child = require('./child.js')(app);
app.get('/', function(req, res){
child.crazyFunction(function(){
res.send(500);
});
});