when.js is a simple javascript namespace loader and requirements handler

Why

when.js makes it so that you don't have to worry about including your JavaScript scripts in order. It allows you to write more modular code and write with graceful degradation in mind.

A simple example

// when window.foo is availabe
when('foo', function(){
    alert('foo is available');
});

// when window.foo.bar is available
when('foo.bar', function(){
    alert('foo.bar is available');
});

// when window.foo.bar.baz is available
when('foo.bar.baz', true, function(){
    alert('foo.bar.baz is available and true');
});

// this is the same as
// window.foo = {
//    bar: {
//        baz: true
//    }
// }
// but will also call the callbacks we set with the when function: 'foo',
// 'foo.bar', and 'foo.bar.baz'
give('foo.bar', {
    baz: true
});

Loading JavaScript libraries

// load jQuery and notify any handlers that the 'jQuery' namespace
// is available when the script has been evaluated
load('jQuery', '/static/js/jquery.js');

// when the jQuery namespace is available, attach an event handler to the
// DOM ready event that alerts "DOM is ready"
when('jQuery', function(){
    $(function(){
        alert('DOM is ready');
    });
})

Loading models, graceful degradation, and logic

// make a call to your RESTful API to get some user info
grab('myapp.current_user', '/users/11/');

when('myapp.current_user.is_logged_in', true, function(){
    // this code only runs if the current user is logged in
});

License

BSD, see the included LICENSE file

Homepage

http://github.com/elijahr/when.js