jsclass

Short-hand setup using autoload

As your application grows you may find that your package configuration becomes repetitive. For example, you may have a set of test scripts that mirror the set of classes in your application:

JS.packages(function() { with(this) {

    file('tests/widget_spec.js')
        .provides('WidgetSpec')
        .requires('MyApp.Widget');

    file('tests/blog_post_spec.js')
        .provides('BlogPostSpec')
        .requires('MyApp.BlogPost');

    file('tests/users/profile_spec.js')
        .provides('Users.ProfileSpec')
        .requires('MyApp.Users.Profile');
});

If you run into this situation you can use the autoload() function to set up packages for objects whose name matches a certain pattern. For example you could compress the above configuration like this:

JS.packages(function() { with(this) {
    autoload(/^(.*)Spec$/, {from: 'tests', require: 'MyApp.$1'});
});

If you require() a package that doesn’t have an explicit configuration, the autoloader will try to figure out where to load it from by matching its name against the set of patterns it knows about. A naming convention is adopted for converting object names to paths: dots convert to path separators, and camelcase names are converted to underscored style. Thus Users.ProfileSpec becomes users/profile_spec.js.

autoload() expects three parameters. The first is a regex that is used to match package names.

The from option is a directory path where packages with that name pattern live, for example this rule would make the package loader look in tests/users/profile_spec.js to find the Users.ProfileSpec module. If you don’t like the convention used for turning object names into paths, you can override it by passing a function as from. The function should take an object name and return a path.

JS.packages(function() { with(this) {
    autoload(/^(.*)Spec$/, {
        from: function(name) { return '/modules/' + name + '.js' },
        require: 'MyApp.$1'
    });
});

The require option lets you specify an object the package depends on, using match results from the regex. The above rule would mean that Users.ProfileSpec has a dependency on MyApp.Users.Profile. You can also pass an array as the require option and each string within will be expaned in this way.