Modules In NodeJs | Node.Js Tutorial #2

Hey Programmers, In the Previous Tutorial We Installed Node.js And Created Our First Hello World Program Using NodeJS And In this Post We will be Learning About Modules In NodeJs And Working With Few Modules In NodeJS Like HTTP, File System, URL etc.

Table Of Contents:

Modules In NodeJS
NodeJS Built-In Modules
List of NodeJs Built-In Modules
Including Modules
Creating Your Own Moule In NodeJS
Include Your Own Module In Any Program
HTTP Module In NodeJs
Creating a Basic Web Server In NodeJS
File System Module In NodeJS
URL Module In NodeJS

Modules In NodeJS

Modules are like JavaScript Libraries as We Work With Libraries, Modules Are Also Same But We Just Use Modules In NodeJS By Installing It With the Help of NPM (Node Package Manager).

NodeJS Built-In Modules

NodeJS has some Set of Built-In Modules Which Can Be Used Without Installing It. We Just Have To Import It In Any Program to Use It.

List of NodeJs Built-In Modules

assert	Provides a set of assertion tests
buffer	To handle binary data
child_process	To run a child process
cluster	To split a single Node process into multiple processes
crypto	To handle OpenSSL cryptographic functions
dgram	Provides implementation of UDP datagram sockets
dns	To do DNS lookups and name resolution functions
domain	Deprecated. To handle unhandled errors
events	To handle events
fs	To handle the file system
http	To make Node.js act as an HTTP server
https	To make Node.js act as an HTTPS server.
net	To create servers and clients
os	Provides information about the operation system
path	To handle file paths
punycode	Deprecated. A character encoding scheme
querystring	To handle URL query strings
readline	To handle readable streams one line at the time
stream	To handle streaming data
string_decoder	To decode buffer objects into strings
timers	To execute a function after a given number of milliseconds
tls	To implement TLS and SSL protocols
tty	Provides classes used by a text terminal
url	To parse URL strings
util	To access utility functions
v8	To access information about V8 (the JavaScript engine)
vm	To compile JavaScript code in a virtual machine
zlib	To compress or decompress files

Including Modules

In Order to Include a Module In a Program. Use require() Function With the Name of the Module:

var http = require('http');

Creating Your Own Moule In NodeJS

As NodeJS Allows us to Work With Other Modules Unlike Of This We can Also Create Our Own Modules In NodeJS And Import It In Other Programs.

Creating a Date Time Module Using the JavaScript Date() Function:

exports.DateTime = function () {
  return Date();
};

Save the File With the filename Module.js

Include Your Own Module In Any Program

var http = require('http');
var DateTime = require('./Module');
http.createServer(function (req, res){
  res.write('Hello World!');
  res.end();
}).listen(3000);

HTTP Module In NodeJs

In Node.js, There is a Bult-In Module Called HTTP (Hyper Text Transfer Protocol) Which Allows Us to Listen to Server Ports & Give the Responce Back to the Client.

To Include the HTTP Module Use the require() Function:

var http = require('http');

Creating a Basic Web Server In NodeJS

const http = require('http')
const port = 3000
const server = http.createServer(function(req ,res){
    res.write('Web Server In Node.js')
    res.end()
})
server.listen(port, function(error) {
    if (error) {
        console.log('Something Went Wrong', error)
    }
    else{
        console.log('Sever Started Sucessfully', + port)
    }
})

File System Module In NodeJS

NodeJS has a Module Called File System which allows Us to Work With Our File System Present In Our Computer.

var fs = require('fs');

Common uses for the File System module:

Read files
Create files
Update files
Delete files
Rename files

Reading Files Using NodeJS

We can Read Files In NodeJS By Using the fs.readFile() FunctionSuppose We Have a File Called index.html In Which We Have the Following Content:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Node.js File System</title>
</head>
<body>
    <h2>Your Are Viewing Through Node.js</h2>
</body>
</html>

Now Create a New File Named Read.js And Copy the Following Code:

var http = require('http');
var file_system = require("fs");

http.createServer(function(req, res){
    fs.readFile('index.html', function(err, data){
        res.writeHead(200, {'Content-Type': 'text/html'});
        res.write(data);
        return  res.end();
    });
}).listen(3000);

Now It Will Read the Index.html File And Give Us the Desired Output.

URL Module In NodeJS

The URL module splits up a web address into readable parts. URL Module Uses the require() method.

var url = requie('url');

Parse an Address Using the url.parse() Function, It Will Return the URL Object With Each Part of the Address as a Property:

var url = require(url);

var adr = 'http://localhost:3000/';
var q = url.parse(adr, true);

console.log(q.host);
console.log(q.pathname);
console.log(q.search);

var qdata = q.query;
console.log(qdata.month);

So This Was It For this Blog, See you In the Next One Till Then Keep Coding Keep Exploring!

Previous NodeJS Tutorials:

Getting Started NodeJS + Writing Hello World! | Node.Js Tutorial #1