Node.js is a set of JavaScript libraries built on Google's V8 JavaScript engine that uses asynchronous and event-driven techniques. It allows for non-blocking I/O operations and callbacks to handle events like timeouts. It is more scalable than traditional threaded models as it uses fewer resources and has no threads. WebSockets and long-polling allow for bidirectional communication with less overhead than HTTP and AJAX. Sanwaad is a real-time chat server designed with a router, controller, views, client-side libraries, and testing suites.

1. Node.js

2. Set of libraries on top of V8

3. Evented I/O e.g. ioOperation(args, callbackFunction );

4. Evented setTimeout(function(){ console.log(“world”);},2000); console.log(“hello”); Sequential print(“hello”); sleep(2); print (“world”);

5. No threads :) More scalable Code in js Benefits

6. WebSocket

7. Full duplex single socket connection

8. Polling Client Server Something new ? NO !!! Something new ? NO !!! Something new ? Yeah! Here it is !

9. Long-Polling = polling with time factor

10. Benefits Bi-directional communication Full duplex Less overhead as compared to HTTP/AJAX

11. Sanwaad

12. The real-time chat server

13. Design Server: app.js – router sanwaad.js – controller index.jade – view

14. Design... Client: landing HTML page lib.css – cascaded stylesheet lib.js – client side java script jquery.js – a js library to write less and do more

15. Design... Testing: qunit.js – javascript test suite utest.js – unit tests testRunner.html – Test Runner

16. Demo

17. Questions ?