Node.JS IntroductionAdam Hendra Brata

Introduction to Node.JS

Javascript vs Node.JS

• Javascript• JavaScript is a language that runs inside web browsers as

part of documents loaded by the browser.

• Javascript gives behaviour to your pages (HTML gives semantic structure, CSS gives form or look and feel).

• Normally, alongside HTML and CSS, JavaScript is one of the three core technologies of World Wide Web content production

Javascript vs Node.JS

• Javascript

Javascript vs Node.JS

• Node.JS• Node.js® is a JavaScript runtime built on Chrome's V8

JavaScript engine.

• Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

• Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.

Javascript vs Node.JS

• Node.JS • Node's goal is to provide an easy way to build scalable

network programs.

• JavaScript usually used in client-side but node.js puts the JavaScript on server-side thus making communication between client and server will happen in same language

• Servers are normally thread based but Node.JS is “Event” based. Node.JS serves each request in a Evented loop that can able to handle simultaneous requests.

• Node.JS programs are executed by V8 Javascript enginethe same used by Google chrome browser.

Synchronous VS Asynchronous I/O

Multi Threaded Server

Node.JS Server

Threads VS Asynchronous Event-driven

Threads Asynchronous Event-driven

Lock application / request with listener-workers threads

only one thread, which repeatedly fetches an event

Using incoming-request model Using queue and then processes it

multithreaded server might block the request which might involve multiple events

manually saves state and then goes on to process the next event

Using context switching no contention and no context switches

Using multithreading environments where listener and workers threads are used frequently to take an incoming-request lock

Using asynchronous I/O facilities (callbacks, not poll/select or O_NONBLOCK) environments

Node.JS Event Loop

Callback is an asynchronous equivalent for a function. A callback function is called at thecompletion of a given task.

Node.JS Processing Model

Node.JS Architecture

Node.JS Libraries

Node.JS

• When to use Node.JS ?• Chat/Messaging

• Real-time Applications

• Intelligent Proxies

• High Concurrency Applications

• Communication Hubs

• Internet of Things Environment

• Embedded System

So……..