lsmith/event-multi-defaultFn.js

## event-multi-defaultFn.js
YUI.add('event-multi-defaultFn', function (Y) {

    // FIXME: publish() needs to be patched to support allowing this to be called before
    // publish().  Today, the publish() call will clobber the AOP wrapper.

    Y.EventTarget.prototype.addEventBehavior = function (type, fn, when) {
        var event = this.getEvent(type),
            method = when === 'before' ? 'before' : 'after',
            handle;

        if (event && event.defaultFn) {
            handle = Y.Do[method](fn, event, 'defaultFn');
        }

        return handle;
    };

    // detach from the returned handle also works, and calls to both
    // handle.detach() and thing.removeEventBehavior(...) should not
    // interfere with the other.
    Y.EventTarget.prototype.removeEventBehavior = function (type, fn, when) {
        var event = this.getEvent(type),
            eventId, doMethod, id;

        if (event && event.defaultFn && fn) {
            eventId = Y.stamp(event);
            doMethod = Y.Do.objs[eventId];
            id = eventId + Y.stamp(fn) + 'defaultFn';

            if (doMethod) {
                if (when) {
                    when = when === 'before' ? when : 'after';
                    delete doMethod.defaultFn[when][id];
                } else {
                    delete doMethod.defaultFn.before[id];
                    delete doMethod.defaultFn.after[id];
                }
            }
        }
    };
}, '0.1', { requires: ['event-custom'] });

## event-multi-defaultFn_manual_test.html
<html lang="en">
<head>
    <title>POC event behavior phase extension</title>
    <meta charset="utf-8">
    <style>
        body { font-family: sans-serif; }
    </style>
</head>
<body>

<h3>Firing with on(), native defaultFn, after()</h3>
<ol id="one"></ol>

<h3>Firing with added behavior after native defaultFn</h3>
<ol id="two"></ol>

<h3>Firing behaviors added before and after native defaultFn</h3>
<ol id="three"></ol>

<h3>Firing again after adding and removing more behaviors</h3>
<ol id="four"></ol>

<script src="http://yui.yahooapis.com/3.4.1/build/yui/yui-min.js"></script>
<script src="event-multi-defaultFn.js"></script>
<script>
YUI({ filter: 'raw' }).use('node', 'event-multi-defaultFn', function (Y) {

    var target = new Y.EventTarget({ emitFacade: true }),
        current = 'one';

    function report(message) {
        Y.one('#' + current).append('<li>' + message + '</li>');
    }

    target.publish('foo', {
        defaultFn: function () {
            report('published defaultFn');
        }
    });

    target.on('foo', function () {
        report('on subscriber');
    });

    target.after('foo', function () {
        report('after subscriber');
    });

    target.fire('foo');

    current = 'two';

    target.addEventBehavior('foo', function () {
        report('after published defaultFn');
    }, 'after');

    target.fire('foo');

    current = 'three';
    target.addEventBehavior('foo', function () {
        report('before published defaultFn');
    }, 'before');

    target.fire('foo');

    current = 'four';
    var handle = target.addEventBehavior('foo', function () {
        report('this should not be logged');
    }, 'before');

    handle.detach();

    function removeMe() {
        report('this should ALSO not be logged');
    }

    target.addEventBehavior('foo', removeMe, 'after');

    target.removeEventBehavior('foo', removeMe, 'after');

    target.fire('foo');

});
</script>
</body>
</html>
	YUI.add('event-multi-defaultFn', function (Y) {

	// FIXME: publish() needs to be patched to support allowing this to be called before
	// publish(). Today, the publish() call will clobber the AOP wrapper.

	Y.EventTarget.prototype.addEventBehavior = function (type, fn, when) {
	var event = this.getEvent(type),
	method = when === 'before' ? 'before' : 'after',
	handle;

	if (event && event.defaultFn) {
	handle = Y.Do[method](fn, event, 'defaultFn');
	}

	return handle;
	};

	// detach from the returned handle also works, and calls to both
	// handle.detach() and thing.removeEventBehavior(...) should not
	// interfere with the other.
	Y.EventTarget.prototype.removeEventBehavior = function (type, fn, when) {
	var event = this.getEvent(type),
	eventId, doMethod, id;

	if (event && event.defaultFn && fn) {
	eventId = Y.stamp(event);
	doMethod = Y.Do.objs[eventId];
	id = eventId + Y.stamp(fn) + 'defaultFn';

	if (doMethod) {
	if (when) {
	when = when === 'before' ? when : 'after';
	delete doMethod.defaultFn[when][id];
	} else {
	delete doMethod.defaultFn.before[id];
	delete doMethod.defaultFn.after[id];
	}
	}
	}
	};
	}, '0.1', { requires: ['event-custom'] });
	<html lang="en">
	<head>
	<title>POC event behavior phase extension</title>
	<meta charset="utf-8">
	<style>
	body { font-family: sans-serif; }
	</style>
	</head>
	<body>

	<h3>Firing with on(), native defaultFn, after()</h3>
	<ol id="one"></ol>

	<h3>Firing with added behavior after native defaultFn</h3>
	<ol id="two"></ol>

	<h3>Firing behaviors added before and after native defaultFn</h3>
	<ol id="three"></ol>

	<h3>Firing again after adding and removing more behaviors</h3>
	<ol id="four"></ol>

	<script src="http://yui.yahooapis.com/3.4.1/build/yui/yui-min.js"></script>
	<script src="event-multi-defaultFn.js"></script>
	<script>
	YUI({ filter: 'raw' }).use('node', 'event-multi-defaultFn', function (Y) {

	var target = new Y.EventTarget({ emitFacade: true }),
	current = 'one';

	function report(message) {
	Y.one('#' + current).append('<li>' + message + '</li>');
	}

	target.publish('foo', {
	defaultFn: function () {
	report('published defaultFn');
	}
	});

	target.on('foo', function () {
	report('on subscriber');
	});

	target.after('foo', function () {
	report('after subscriber');
	});

	target.fire('foo');

	current = 'two';

	target.addEventBehavior('foo', function () {
	report('after published defaultFn');
	}, 'after');

	target.fire('foo');

	current = 'three';
	target.addEventBehavior('foo', function () {
	report('before published defaultFn');
	}, 'before');

	target.fire('foo');

	current = 'four';
	var handle = target.addEventBehavior('foo', function () {
	report('this should not be logged');
	}, 'before');

	handle.detach();

	function removeMe() {
	report('this should ALSO not be logged');
	}

	target.addEventBehavior('foo', removeMe, 'after');

	target.removeEventBehavior('foo', removeMe, 'after');

	target.fire('foo');

	});
	</script>
	</body>
	</html>