We have seen the Nodejs Tutorial steps in the previous blog. Now lets understand the main and commonly used components and the modules in the Node.js and its usage in the Node.js application.

Node.js Components

Node.js uses the below given components:

• Import required modules: Node.js application use the require directive to load the node.js modules

var http = require(“http”);  

• Create Server: The server which listens to the node.js application request
• Request & Response: The node.js server will intercept the requests from the browser / console and returns the response back to the client application.

Refer the below program which makes the use of these components

var http = require(‘http’);
var requestListener = function (req, res) {
res.writeHead(200);
res.end(‘Hello, World!’);
}

var server = http.createServer(requestListener);
server.listen(8080, function() { console.log(“Listening on port 8080”)})

Node.js modules

Node.js is built on JavaScript framework and creates .js files for processing. Node.js modules provides the functionality to add the encapsulation logic for segregating the functionality into different modules. Node.js provides the below available modules :

• Express Framework: The provides the features to develop robust web and mobile applications
• MongoDB: provides support for the MondoDB and Node.js integration for database operations
• Restify: Framework to support REST APIs integration
• Jade: provides high performance template engine for nodes and browsers
• Bluebird: provides promise library with full of feature and performance enhancements
• Socket.io: provides real -time bi-directional event based communication, mpostly use for developing chat application
  

Node.js build modules

Node.js provides the in-built modules for processing the java script application.

Module Name	Module Description
assert	Provides a set of assertion tests
buffer	handles binary data
child_process	for running the child processes
cluster	manages multiple node processing
crypto	manages OpenSSL cryptographic functions
dgram	manages UDP datagram sockets
dns	manages DNS Lookup and name resolution functions
domain	deprecated now.
events	manages events
fs	manages file system
http	manages node.js to run as HTTP Server
https	manages node.js to run as HTTPS Server
net	helps in creating server & clients
os	provides operating system data
path	manages file path
punycode	deprecated now
querystring	manages URL query strings
readline	manages readable streams one line at the time
stream	manages streaming data
string_decoder	decodes buffer objects to strings
timers	execute a function after a given number of milliseconds
tls	manages TLS and SSL protocols
tty	Provides classes used by a text terminal
url	parse URL strings
util	provides utility functions
v8	accesses information about V8 (the JavaScript engine)
vm	compiles JavaScript code in a virtual machine
zlib	compress or decompress files