This document discusses Narwhal, a CommonJS implementation that runs on multiple JavaScript interpreters like Rhino, V8, and JavaScriptCore. It describes CommonJS as a standard environment that allows JavaScript code to use the same APIs across different interpreters. Narwhal is highlighted as one of the most mature CommonJS implementations, with Rhino having the most complete support. The document also provides an overview of how Narwhal implements CommonJS packages and modules.

1. Narwhal
and the Adventures of CommonJS
Clinton R. Nixon

2. CommonJS
promises to be a standard environment that
will let JavaScript code use the same APIs
with different interpreters

3. Why?
JavaScript is simple and widely-­‐known.
To succeed, server-­‐side JavaScript must avoid
the fate of Lisp.

4. CommonJS standards
Modules
Packages
System
Binary
Filesystem
Unit Testing

5. CommonJS implementations
Narwhal (Rhino, v8, JSC)
Flusspferd (Spidermonkey/C++)
node.js (v8; not many standards or proposals implemented)
v8cgi (v8)
GPSEE (Spidermonkey/C)
RingoJS (Rhino; was Helma NG)
Perservere (Rhino)
SproutCore (in-­‐browser)

6. Narwhal
one of the most mature CommonJS implementations

7. Narwhal
A CommonJS platform or implementation
Arguably the most mature implementation
Runs on several interpreters
Rhino has the most complete implementation
JavaScriptCore works well on Macs
Easy to add new engines if you're a language
implementation hacker

8. Why?
You can use it today
Rhino makes it easy to build off Java libraries
Lots of activity, and other implementations are
working to be compatible with it
But still needs lots of work

9. Narwhal packages
package.json
Based on the CommonJS local.json
bin/
package standard
lib/
tusk is a package manager foo.js
src/
sea is an environment manager jars/
packages/
Every project is a package engines/
tests/
foo.tests.js

10. package.json
{
"name": "jake",
"author": "Francisco Tolmasky <francisco@280north.com>",
"contributors": [
"Tom Robinson (http://tlrobinson.net/) <tom@280north.com>"
],
"description": "A build system for CommonJS, lifted from Rake",
"keywords": [
"build",
"jake",
"rake",
"make"
],
"version": "0.2.1"
}

11. Modules
Each JS file under lib/ is a module
Modules are executed within a function
Arguments are require, exports, and module
Modules return exports
Core concept of CommonJS

12. Module & package
demonstration

14. Testing demonstration

16. Package management

17. sources.json
{
"version": 2,
"includes": ["http://github.com/280north/narwhal/raw/master/
catalog-­‐2.json"],
"sources": {
"dice": {
"type": "github",
"user": "crnixon",
"name": "narwhal-­‐dice"
},
"caffeine": {
"type": "github",
"user": "crnixon",
"name": "narwhal-­‐caffeine"
}
}
}

18. Important packages
jack
jake
jsdocs
ejs
nitro
bogart

19. Real apps I wrote

20. Questions and discussion
http://narwhaljs.org/
Email me at Clinton R. Nixon <crnixon@gmail.com>
http://pinboard.in/u:crnixon/t:talk:narwhal/