Hello World with Narwhal and Jack
Narwhal allows you to create local or server-side JavaScript applications. It’s made by 280north who also developed Atlas. Narwhal is a beast:
- Narwhal itself is a platform that’s designed to be multi-interpreter and cross-platform
- Rhino has the most complete interpreter support
- Narwhal has a standard library that conforms to the CommonJS standard
- A package manager is provided, called Tusk
This tutorial is based on the hello-web example from the Narwhal documentation. You’ll build a tiny web app that can return text, all from JavaScript.
Installation
Downloaded it from the narwhal repository. There’s a zip file, or just use git:
git clone git://github.com/tlrobinson/narwhal.git
Environments
Narwhal makes a JavaScript interpreter and several scripts (including tusk) available. To get your shell into a suitable state, run bin/sea from the narwhal directory. Confirm everything works by typing narwhal.
Tusk and Jack
Tusk can install remote packages. Try typing tusk search json to view some JSON-related packages. Typing tusk install package-name will install a package.
Let’s use tusk to create our own app:
tusk init hello-web
cd hello-web
Then install jack:
tusk install jack
This command added jack to your hello-web project. Jack makes communicating with web servers easier — it’s based on highly successful projects from the Ruby and Python communities.
Hello, world
Jack expects a file called jackconfig.js. Create one that looks like this:
exports.app = function(env) {
var text = "Hello, world!";
return {
status : 200,
headers : { "Content-Type" : "text/plain", "Content-Length" : String(text.length) },
body : [text]
};
};
From the same directory run jackup and visit http://127.0.0.1:8080/.
Documentation
Narwhal comes with documentation in the docs/ folder. There’s enough in there about packaging, the standard library and narwhal’s environment to keep you busy for a while.