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/*! | |
* jQuery Tiny Pub/Sub for jQuery 1.7 - v0.1 - 27/10/2011 | |
* Based on @cowboy Ben Alman's REALLY tiny pub/sub. | |
* 1.7 specific updates by @addyosmani. | |
* Copyright maintained by @cowboy. | |
* Dual licensed under the MIT and GPL licenses. | |
*/ | |
(function($){ | |
// Create a "dummy" jQuery object on which to call on, off and trigger event | |
// handlers. Although using {} throws errors here in older versions of jQuery | |
// if you are using 1.7, you won't have this issue. | |
var o = $({}); | |
// Subscribe to a topic. Works just like on, except the passed handler | |
// is wrapped in a function so that the event object can be stripped out. | |
// Even though the event object might be useful, it is unnecessary and | |
// will only complicate things in the future should the user decide to move | |
// to a non-$.event-based pub/sub implementation. | |
$.subscribe = function( topic, fn ) { | |
// Call fn, stripping out the 1st argument (the event object). | |
function wrapper() { | |
return fn.apply( this, Array.prototype.slice.call( arguments, 1 ) ); | |
} | |
// Add .guid property to function to allow it to be easily unbound. Note | |
// that $.guid is new in jQuery 1.4+, and $.event.guid was used before. | |
wrapper.guid = fn.guid = fn.guid || ( $.guid ? $.guid++ : $.event.guid++ ); | |
// Bind the handler. | |
o.on( topic, wrapper ); | |
}; | |
// Unsubscribe from a topic. | |
$.unsubscribe = function() { | |
o.off.apply( o, arguments ); | |
}; | |
// Publish a topic | |
$.publish = function() { | |
o.trigger.apply( o, arguments ); | |
}; | |
})(jQuery); |
Note 2: This is really just a proof of concept. I would almost always recommend using the original (unless we can show there are significant perf benefits to using .on/.off directly over the (now) abstracted .bind()/.unbind() versions etc).
@addy: My guess is that the on/off implementation above should be faster when compared to the previous implementation (bind/unbind) using 1.7. It should only be slightly faster because bind/unbind are just one line wrappers around the on/off methods http://o61.go.ly
With that in mind the on/off methods in 1.7 could very well be slower than the bind/unbind methods in 1.6.4. That would be an interesting comparison. I hope the answer is better performance in 1.7 & not worse ;)
Hi Andy
Excellent pattern. BUt I am having some problems on the context of the callback function. Example:
$.subscribe("dashboard.updateData", this.updateData ); //this--> currenct object
then :
updateData: function(){
this--> here is the event object, but here I will need the original object
}
Is there a way to make callbacks fire in scope of originating object instead ?
And demo: http://jsfiddle.net/58RnW/