mod is a function for defining and loading JS modules from a browser.
It serves as a method to break your project into a tree of maintainable
pieces that depend on each other, much like an include or import statement.
Once your project is loaded you may use mod to compile your code into one
monolithic closure.
mod uses initialization objects (called packages, internally) to define
modules. An initialization object takes a name, an array of dependencies
and an init function, which by my convention always returns a constructor.
Include mod.js in your <head>:
<script src="mod.js" type="text/javascript" charset="utf-8"></script>and then set up your a module:
<script type="text/javascript" charset="utf-8"> // create a main module
mod({
name : 'SomeModule',
dependencies : [
'path/to/AnotherModule.js',
'path/to/YetAnotherModule.js'
],
init : function initMain(AnotherModule, YetAnotherModule) {
// We can access AnotherModule and YetAnotherModule because mod.js
// initializes dependencies in order and provides them to your init
// in the order that you declare them in the dependencies array above...
function SomeConstructor() {
this.foo = "bar";
}
SomeConstructor.prototype = {
anotherInstance : new AnotherModule(),
yetAnotherInstance : new YetAnotherInstance()
};
return SomeConstructor;
}
});</script>In this first call mod packages your module and starts loading its dependencies (either through XMLHttpRequest or script tag injection).
Once the dependencies are loaded, which probably define more modules and load more scripts, the result of the init function is stored in mod.modules, in this case as mod.modules.SomeModule, so they don't clutter global space.
The initialized modules are provided to other init functions in the order they are asked for.
As an added benefit, you can share data between modules using mod.modules.
If you use mod to write lots of modules (when you're making a big project) mod can 'compile' your project for you, removing all instances of mod.
It essentially takes all your init functions and prints them to one monolithic file, which you can then compress with YUI or Google Closure.
To do this, load your project in your browser, open the js console and type mod.printCompilation(). Alternatively, to store in a string, type var compilation = mod.compile();.
For more examples check out my other project bang at https://github.com/schell/bang
Notes
In development situations the scripts mod loads can change often. In order to avoid the browser cacheing these files (and returning an old version of your scripts) set mod.nocache = true, which will enable the "force re-download" feature. Unfortunately with mod.nocache set to true, many javascript debuggers can't set breakpoints on the loaded scripts. Keep this in mind.