Modules

Node has a simple module loading system. In Node, files and modules are in one-to-one correspondence. As an example, app.js loads the module hello.js  and custom_goodbye.js in the same directory.

//hello.js
var hello = function(){
    console.log("hello");
}
module.exports = hello;

//custom_goodbye.js
exports.goodbye = function(){
 console.log("bye!");
}

//app.js
var hello = require('./hello');
var gb = require('./custom_goodbye');
hello();
gb.goodbye();

Path

var the_module = require('./path_module'); // look in same directory
var the_module = require('../path_module'); // look in parent directory
var the_module = require('/path_module'); // look in absolute path

Depending your dependencies

create package.json filename like this following code:

{
  "name": "my-application-name",
  "description": "Try to learning nodejs",
  "version": "0.0.1",
  "author": {
    "name":"Andy",
    "email":"sintret@gmail.com"
  },
  "dependencies" : {
    "connect":"~1.8.7"
  }
}

$ npm install

install into the node_modules directory : my_app/node_modules/connect

Semantic versioning

"connect" : "1.8.7"   explains => 1 = major 8 = minor 7 = patch Ranges
"connect" : "~1" is same >= 1.0.0 < 2.0.0
"connect": "~1.8" is same >= 1.8.0 <1.9.0