<p>Implementers MAY provide this method definition.</p>

<p>Implement this function if you want extra data extracted during processArgs to be propagated to subscriptions on a per-node basis. That is to say, if you call <code>Y.on('xyz', fn, xtra, 'div')</code> the data returned from processArgs will be shared across the subscription objects for all the divs. If you want each subscription to receive unique information, do that processing here.</p>

<p>The default implementation adds the data extracted by processArgs to the subscription object as <code>sub._extra</code>.</p>

<p>Implementers SHOULD provide this method definition.</p>

<p>Implementation logic for subscriptions done via <code>node.delegate(type, fn, filter)</code> or <code>Y.delegate(type, fn, container, filter)</code>. Like with <code>on()</code> above, this function should monitor the environment for the event being fired, and trigger subscription execution by calling <code>notifier.fire(e)</code>.</p>

<p>This function receives a fourth argument, which is the filter used to identify which Node's are of interest to the subscription. The filter will be either a boolean function that accepts a target Node for each hierarchy level as the event bubbles, or a selector string. To translate selector strings into filter functions, use <code>Y.delegate.compileFilter(filter)</code>.</p>

<p>Implementers SHOULD provide this method definition.</p>

<p>Implementation logic for detaching subscriptions done via <code>node.on(type, fn)</code>. This function should clean up any subscriptions made in the <code>on()</code> phase.</p>

<p>Implementers SHOULD provide this method definition.</p>

<p>Implementation logic for detaching subscriptions done via <code>node.delegate(type, fn, filter)</code> or <code>Y.delegate(type, fn, container, filter)</code>. This function should clean up any subscriptions made in the <code>delegate()</code> phase.</p>

Returns the detach handles of subscriptions on a node that satisfy a search/filter function. By default, the filter used is the <code>subMatch</code> method.

<p>Implementers SHOULD provide this method definition.</p>

Implementation logic for subscriptions done via <code>node.on(type, fn)</code> or <code>Y.on(type, fn, target)</code>. This function should set up the monitor(s) that will eventually fire the event. Typically this involves subscribing to at least one DOM event. It is recommended to store detach handles from any DOM subscriptions to make for easy cleanup in the <code>detach</code> method. Typically these handles are added to the <code>sub</code> object. Also for SyntheticEvents that leverage a single DOM subscription under the hood, it is recommended to pass the DOM event object to <code>notifier.fire(e)</code>. (The event name on the object will be updated).

<p>Implementers MAY provide this method definition.</p>

<p>Implement this function if the event supports a different subscription signature. This function is used by both <code>on()</code> and <code>delegate()</code>. The second parameter indicates that the event is being subscribed via <code>delegate()</code>.</p>

<p>Implementations must remove extra arguments from the args list before returning. The required args for <code>on()</code> subscriptions are</p> <pre><code>[type, callback, target, context, argN...]</code></pre>

<p>The required args for <code>delegate()</code> subscriptions are</p>

<pre><code>[type, callback, target, filter, context, argN...]</code></pre>

<p>The return value from this function will be stored on the subscription in the '_extra' property for reference elsewhere.</p>

<p>Implementers MAY override this to define what constitutes a "same" subscription. Override implementations should consider the lack of a comparator as a match, so calling <code>getSubs()</code> with no arguments will return all subs.</p>

<p>Compares a set of subscription arguments against a Subscription object to determine if they match. The default implementation compares the callback function against the second argument passed to <code>Y.on(...)</code> or <code>node.detach(...)</code> etc.</p>