Node.js Module Globals Example

a.js

var b = require(__dirname + "/b"),
    c = require(__dirname + "/c");

b.doIt();
console.log(c.get()); //Outputs 'b.doIt is updating stuff!'

b.js

var c = require(__dirname + '/c');

module.exports.doIt = function() {
  c.update("b.doIt is updating stuff!");
}

c.js

var x;

module.exports.update = function(y) {
  x = y;
}

module.exports.get = function() {
  return x;
}