Friday, May 17, 2013

Trigger 1.0.0 - Application Events Go Native

Ok, i've written about the trigger library before, but a lot has changed since then. jQuery has gone modular and IE8 has drifted out of my development priorities making native wheels a reality.  In response, trigger.js has changed as well.   It's reached version 1.0.0 and staked out a place on GitHub, NPM and Bower.  The official documentation can now be enjoyed here.

Here's an overview of what's changed is the last year:

  • What's New:
    • Native support - You don't need jQuery, but if you do use jQuery everything still just works.
    • Better sequence control - e.stopSequence(), e.resumeSequence() and e.isSequenceStopped()
    • Async sequences - Use e.stopSequence(promise) and when the promise resolves, the sequence resumes.
    • Event categories - If event type is a verb, constants (formerly "data") are the object, and tags are the adjectives, event.category is the subject that was missing from the grammar.
    • Triggers besides click/enter - You can now declare application events to be triggered by any native (or custom) event via calls like trigger.add('dblclick');
    • Special event extensions - You can set up special handlers for particular event types.
    • Grunt build
    • QUnit test suite
  • What's Different:
    • tags use # instead of : - the colon was stolen and the tags got a more standard syntax
    • event.data is now event.constants - better describes the hard-coded nature of the property
    • trigger="foo" is now click="foo" - more triggers required a more flexible attribute declaration
  • What's Gone:
    • The $.fn.trigger wrapper. With jQuery optional and declarative triggering being the recommended pattern, the byte tax for the manual shortcut was deemed not-worth-it. It's a tiny little jquery.trigger.js extension now.
    • IE 6,7,8 support. These don't support custom application events, so you'll need both jQuery and the tiny trigger.old.js extension to make things work in older IE versions.  Oh, and IE 6 and 7 require a JSON polyfill as well.
    • e.preventDefault() to stop event sequences. The overlap of meaning was confusing, caused problems in IE9, and couldn't support promises. Use e.stopSequence()!
    • jQuery event data == e.data.  e.data became e.constants and application event listeners no longer receive data as additional parameters. Again, the overlap of meaning was a problem and the switch to native events offered no way to pass listeners extra parameters anyway. Support for this is under consideration for jquery.trigger.js, but it would mean triggered event sequences could not be heard outside jQuery's event system.