Node.Js

Delivered this talk on Node.js in GDG Developers Conclave @ Rajkot.

It gives basic idea about node.js. How node.js works? How easily we can get started with node.

Transcript

1. By: Megha Sanghvi Infostretch Corporation
2. Agenda • Introduction • Current System vs Node JS • Async vs Sync • Event Mechanism • REPL • Global Object • Modules • Express •Npm – Node Package Manager •Publish Custom Package •Q&A
3. Introduction • JavaScript Runtime • Built upon V8 engine • Written in 2009 by Ryan Dhal • Non blocking I/O • Run without browser • Server side web applications
4. Current System vs Node JS • Complex to build server on existing High end technology. • Server and client side can be build in single technology. • Built upon observer pattern for single thread between multiple request • Single Thread - Node js • Multiple Thread - Current high end servers • Context switching
5. Async vs Sync Async: Send query/request Continue to execute other piece of code Whenever query/request result comes send it to callbacks Sync: Send query/request Wait for result to come for query/request
6. Sync: var data = db.query(‘....’); console.log(data); Async: db.query(‘..’,function(data){ // Do whatever we want to do with data });
7. Event Mechanism • Everything in Node JS is event based. • It runs on event based loop. • Register for event and whenever it fires caller will be notified. • Don’t need to wait for event to be complete. • Callbacks
8. REPL • Read Eval Print Loop • Interactively run JavaScript • Command line interface for node • Debugging, Testing or just trying out • Multiline function allowed • Run : node • .help • _ - reserved for last expression result
9. Global Object • Global object in node.js • Top level scope • Process object • require - Node module loading system • Similar to window object which we are having in browser
10. Modules • Everything in Node JS is module. • Types of module • Built in module • Custom module • How to import modules in Node JS? • Example for module
11. Npm – Node Package Manager • What is npm? •Built in package manager for Node •Npm Repository • How to install package using npm? •Search for specific package in npmjs.com and run npm command • What is package.json? •Contains metadata about app or module. • How to create package.json?
12. NPM •Convenient way to manage your node.js dependencies. •When someone takes our project, they can directly run “npm install” •-g : Globally install •without -g install locally
13. Express • Web application framework. • Rapid development of Node based web applications. • Set up middlewares to response HTTP request. • Routing mechanism simplified.
14. Publish module • Publish module to npm registry • npm adduser • Publish Module • npm publish • npm unpublish
15. Questions & Answers