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@dharFr

dharFr/jquery.observer.js

Created February 28, 2012 00:39
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jQuery based observer pattern
Raw
jquery.observer.js
;(function($) {
/*
* jQuery Observer pattern
* inspired by @addyosmani 's code
* see: http://addyosmani.com/resources/essentialjsdesignpatterns/book/#highlighter_506612
*/
var topics = [];
function getTopic(id) {
var callbacks;
topic = id && topics[id];
if (!topic) {
callbacks = $.Callbacks();
topic = {
publish: callbacks.fire,
subscribe: callbacks.add,
unsubscribe: callbacks.remove
};
if (id) topics[id] = topic;
}
return topic;
}
$.observer = {
publish: function(id) {
var args = (2 <= arguments.length) ? Array.prototype.slice.call(arguments, 1) : [];
var t = getTopic(id);
return t.publish.apply(t, args);
},
subscribe: function(id, fn) {
return getTopic(id).subscribe(fn);
},
unsubscribe: function(id, fn) {
return getTopic(id).unsubscribe(fn);
}
};
})(jQuery);
Raw
observer-sample.html
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>jQuery Observer Pattern Sample</title>
</head>
<body>
<p>Outputs to console...</p>
<script src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
<script src="jquery.observer.js"></script>
<script>
function fn1() { console.log('fn1 called', arguments); }
function fn2() { console.log('fn2 called', arguments); }
function fn3() { console.log('fn3 called', arguments); }
function publish() {
var args = (1 <= arguments.length) ? Array.prototype.slice.call(arguments, 0) : [];
console.group('publish ' + args[0]);
$.observer.publish.apply($.observer, args);
console.groupEnd();
}
$.observer.subscribe('test1', fn1);
$.observer.subscribe('test1', fn2);
$.observer.subscribe('test2', fn3);
publish('test1', 'strArg1', 'strArg2');
publish('test2', 1, 2, '3');
$.observer.unsubscribe('test1', fn2);
publish('test1', {key1: 'val1', key2: 'val2'});
publish('test2');
$.observer.unsubscribe('test1', fn1);
publish('test1');
publish('test2');
</script>
</body>
</html>
@pucheta
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pucheta commented Feb 10, 2014

Hello dharFr. Thanks for this script! I was making an object to perform the observer pattern, but i don't knew nothing about the jQuey Callbacks Object. This code is better. I've been testing your script in my code and works excellent!
Thanks again for the script, the knowledge of jQuery Callbacks and the link to the JavaScript Design Patterns book. Very useful all :)

@danielsedlacek
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Thanks, this is very useful. I'd like to contribute with typescript definition

interface JQueryStatic {
    observer : Observer;
}

interface Observer {
    publish(event : string, ...args: any[]);
    subscribe(event : string, handler : Function);
    unsubscribe(event : string, handler : Function);
}

@jhyland87
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Very useful! I wanted to add a suggestion. For the plugin system im using, in PHP, you would do something like...

add_action('asset.add.success', 'my_function');
or
add_action('asset.add.error', 'my_function');

and if you wanted to have my_function() execute on both success AND error, you could just..

add_action('asset.add', 'my_function');

and it would execute on asset.add.*, do you think theres a way to do that with your jQuery plugin? Or can you make it do that? :-D

@jhyland87
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Is there a way to use this to allow observers alter data? as opposed to just fire off functions that are subscribed to an event?

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