module.exports in Node.js

Suppose you want to write a module, say a functions module and access it in another module, say main.js, how are you going to do it in Node.js?

Real simple!

Create two .js files under C:\nodetest folder: functions.js, main.js

functions.js
module.exports = { addNumbers : function() { var total = 0; for (var a = 0; a < arguments.length; a++){ total += parseInt(arguments[a]); } return total; }, findArea : function(r){ return 3.142 * r * r; } };

or 

functions.js:
this.addNumbers = function() { var total = 0; for (var a = 0; a < arguments.length; a++){ total += parseInt(arguments[a]); } return total; }; this.findArea = function(r){ return 3.142 * r * r; };

main.js
var functions = require('./functions.js'); console.log(functions.addNumbers(1,2)); console.log(functions.findArea(2));

Run the main.js from command prompt!

C:\nodetest>node main

Reference:

http://www.sitepoint.com/understanding-module-exports-exports-node-js/