NodeJS flashcards

1. NodeJS

2. Milestones
● Server-side Javascript based on Google V8
● Non-blocking Input/Output event model
● 100% CPU using: one process - one thread -
one core

3. Google V8
● V8 JavaScript VM is used in Google Chrome
● No JIT, all JavaScript is compiled to
assembler
● Hidden classes optimization from Self (V8 does not
dynamically lookup access properties, instead it uses hidden classes that are created behind the
scene)
● Improved garbage collector

4. Non-blocking I/O
The non-blocking nature makes node.js a good
fit for comet and next generation realtime web-
applications
nginx: non-blocking
apache: threaded
non-blocking can handle more requests-per-second and uses a lot less memory

5. NodeJS Perks: front- and backend
● One Javascript - different approaches
● Common libs
● Unit-tests for both sides

6. NodeJS Perks: Frameworks
Native example:
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {
'Content-Type': 'text/plain'
});
res.end('Hello Worldn');
}).listen(3000, '127.0.0.1');
ExpressJS:
var app = express.createServer();
app.get('/', function(req, res){
res.send('Hello World');
});
app.listen(3000);

7. NodeJS Perks: Comet
Comet is a web application model in which a long-held HTTP request allows
a web server to push data to a browser, without the browser explicitly
requesting it.
● Comet servers need to have a lot of open connections
● One thread-per-connection does not scale
● The solution is to use event based servers
● It’s only possible to create event based servers in
node.js

8. NodeJS Weaknesses
● Due to Javascript flexible nature it's hard to
locate mistakes
● Strict convention rules are highly
recommended
● One process serve plenty requests: so,
mistake in one request may "freeze" other.
● Non-trivial garbage collector (closures, long-term
processes)
● Strange open-source community (no standards)
● No backward compatibility

9. NodeJS Scalability

10. NodeJS Scalability

11. Resources
1. http://nodejs.org
2. www.nodebeginner.ru
3. http://pacemaker.pp.ua/presentations/Yura_Bogdanov-nodejs_inside_tactoom.ppt
4. http://code.google.com/p/v8/