/**
* Define new DOM events that can be subscribed to from Nodes.
*
* @module event
* @submodule event-synthetic
*/
var DOMMap = Y.Env.evt.dom_map,
toArray = Y.Array,
YLang = Y.Lang,
isObject = YLang.isObject,
isString = YLang.isString,
query = Y.Selector.query,
noop = function () {};
/**
* <p>The triggering mechanism used by SyntheticEvents.</p>
*
* <p>Implementers should not instantiate these directly. Use the Notifier
* provided to the event's implemented <code>on(node, sub, notifier)</code> or
* <code>delegate(node, sub, notifier, filter)</code> methods.</p>
*
* @class SyntheticEvent.Notifier
* @constructor
* @param handle {EventHandle} the detach handle for the subscription to an
* internal custom event used to execute the callback passed to
* on(..) or delegate(..)
* @param emitFacade {Boolean} take steps to ensure the first arg received by
* the subscription callback is an event facade
* @private
* @since 3.2.0
*/
function Notifier(handle, emitFacade) {
this.handle = handle;
this.emitFacade = emitFacade;
}
/**
* <p>Executes the subscription callback, passing the firing arguments as the
* first parameters to that callback. For events that are configured with
* emitFacade=true, it is common practice to pass the triggering DOMEventFacade
* as the first parameter. Barring a proper DOMEventFacade or EventFacade
* (from a CustomEvent), a new EventFacade will be generated. In that case, if
* fire() is called with a simple object, it will be mixed into the facade.
* Otherwise, the facade will be prepended to the callback parameters.</p>
*
* <p>For notifiers provided to delegate logic, the first argument should be an
* object with a "currentTarget" property to identify what object to
* default as 'this' in the callback. Typically this is gleaned from the
* DOMEventFacade or EventFacade, but if configured with emitFacade=false, an
* object must be provided. In that case, the object will be removed from the
* callback parameters.</p>
*
* <p>Additional arguments passed during event subscription will be
* automatically added after those passed to fire().</p>
*
* @method fire
* @param e {EventFacade|DOMEventFacade|Object|any} (see description)
* @param arg* {any} additional arguments received by all subscriptions
* @private
*/
Notifier.prototype.fire = function (e) {
// first arg to delegate notifier should be an object with currentTarget
var args = toArray(arguments, 0, true),
handle = this.handle,
ce = handle.evt,
sub = handle.sub,
thisObj = sub.context,
delegate = sub.filter,
event = e || {};
if (this.emitFacade) {
if (!e || !e.preventDefault) {
event = ce._getFacade();
if (isObject(e) && !e.preventDefault) {
Y.mix(event, e, true);
args[0] = event;
} else {
args.unshift(event);
}
}
event.type = ce.type;
event.details = args.slice();
if (delegate) {
event.container = ce.host;
}
} else if (delegate && isObject(e) && e.currentTarget) {
args.shift();
}
sub.context = thisObj || event.currentTarget || ce.host;
ce.fire.apply(ce, args);
sub.context = thisObj; // reset for future firing
};
/**
* <p>Wrapper class for the integration of new events into the YUI event
* infrastructure. Don't instantiate this object directly, use
* <code>Y.Event.define(type, config)</code>. See that method for details.</p>
*
* <p>Properties that MAY or SHOULD be specified in the configuration are noted
* below and in the description of <code>Y.Event.define</code>.</p>
*
* @class SyntheticEvent
* @constructor
* @param cfg {Object} Implementation pieces and configuration
* @since 3.1.0
* @in event-synthetic
*/
function SyntheticEvent() {
this._init.apply(this, arguments);
}
Y.mix(SyntheticEvent, {
Notifier: Notifier,
/**
* Returns the array of subscription handles for a node for the given event
* type. Passing true as the third argument will create a registry entry
* in the event system's DOM map to host the array if one doesn't yet exist.
*
* @method getRegistry
* @param node {Node} the node
* @param type {String} the event
* @param create {Boolean} create a registration entry to host a new array
* if one doesn't exist.
* @return {Array}
* @static
* @protected
* @since 3.2.0
*/
getRegistry: function (node, type, create) {
var el = node._node,
yuid = Y.stamp(el),
key = 'event:' + yuid + type + '_synth',
events = DOMMap[yuid] || (DOMMap[yuid] = {});
if (!events[key] && create) {
events[key] = {
type : '_synth',
fn : noop,
capture : false,
el : el,
key : key,
domkey : yuid,
notifiers : [],
detachAll : function () {
var notifiers = this.notifiers,
i = notifiers.length;
while (--i >= 0) {
notifiers[i].detach();
}
}
};
}
return (events[key]) ? events[key].notifiers : null;
},
/**
* Alternate <code>_delete()</code> method for the CustomEvent object
* created to manage SyntheticEvent subscriptions.
*
* @method _deleteSub
* @param sub {Subscription} the subscription to clean up
* @private
* @since 3.2.0
*/
_deleteSub: function (sub) {
if (sub && sub.fn) {
var synth = this.eventDef,
method = (sub.filter) ? 'detachDelegate' : 'detach';
this.subscribers = {};
this.subCount = 0;
synth[method](sub.node, sub, this.notifier, sub.filter);
synth._unregisterSub(sub);
delete sub.fn;
delete sub.node;
delete sub.context;
}
},
prototype: {
constructor: SyntheticEvent,
/**
* Construction logic for the event.
*
* @method _init
* @protected
*/
_init: function () {
var config = this.publishConfig || (this.publishConfig = {});
// The notification mechanism handles facade creation
this.emitFacade = ('emitFacade' in config) ?
config.emitFacade :
true;
config.emitFacade = false;
},
/**
* <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>
*
* @method processArgs
* @param args {Array} parmeters passed to Y.on(..) or Y.delegate(..)
* @param delegate {Boolean} true if the subscription is from Y.delegate
* @return {any}
*/
processArgs: noop,
/**
* <p>Implementers MAY override this property.</p>
*
* <p>Whether to prevent multiple subscriptions to this event that are
* classified as being the same. By default, this means the subscribed
* callback is the same function. See the <code>subMatch</code>
* method. Setting this to true will impact performance for high volume
* events.</p>
*
* @property preventDups
* @type {Boolean}
* @default false
*/
//preventDups : false,
/**
* <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).
*
* @method on
* @param node {Node} the node the subscription is being applied to
* @param sub {Subscription} the object to track this subscription
* @param notifier {SyntheticEvent.Notifier} call notifier.fire(..) to
* trigger the execution of the subscribers
*/
on: noop,
/**
* <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>
*
* @method detach
* @param node {Node} the node the subscription was applied to
* @param sub {Subscription} the object tracking this subscription
* @param notifier {SyntheticEvent.Notifier} the Notifier used to
* trigger the execution of the subscribers
*/
detach: noop,
/**
* <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>
*
* @method delegate
* @param node {Node} the node the subscription is being applied to
* @param sub {Subscription} the object to track this subscription
* @param notifier {SyntheticEvent.Notifier} call notifier.fire(..) to
* trigger the execution of the subscribers
* @param filter {String|Function} Selector string or function that
* accepts an event object and returns null, a Node, or an
* array of Nodes matching the criteria for processing.
* @since 3.2.0
*/
delegate : noop,
/**
* <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>
*
* @method detachDelegate
* @param node {Node} the node the subscription was applied to
* @param sub {Subscription} the object tracking this subscription
* @param notifier {SyntheticEvent.Notifier} the Notifier used to
* trigger the execution of the subscribers
* @param filter {String|Function} Selector string or function that
* accepts an event object and returns null, a Node, or an
* array of Nodes matching the criteria for processing.
* @since 3.2.0
*/
detachDelegate : noop,
/**
* Sets up the boilerplate for detaching the event and facilitating the
* execution of subscriber callbacks.
*
* @method _on
* @param args {Array} array of arguments passed to
* <code>Y.on(...)</code> or <code>Y.delegate(...)</code>
* @param delegate {Boolean} true if called from
* <code>Y.delegate(...)</code>
* @return {EventHandle} the detach handle for this subscription
* @private
* since 3.2.0
*/
_on: function (args, delegate) {
var handles = [],
selector = args[2],
method = delegate ? 'delegate' : 'on',
nodes, handle;
// Can't just use Y.all because it doesn't support window (yet?)
nodes = (isString(selector)) ? query(selector) : toArray(selector);
if (!nodes.length && isString(selector)) {
handle = Y.on('available', function () {
Y.mix(handle, Y[method].apply(Y, args), true);
}, selector);
return handle;
}
Y.each(nodes, function (node) {
var subArgs = args.slice(),
extra, filter;
node = Y.one(node);
if (node) {
extra = this.processArgs(subArgs, delegate);
if (delegate) {
filter = subArgs.splice(3, 1)[0];
}
// (type, fn, el, thisObj, ...) => (fn, thisObj, ...)
subArgs.splice(0, 4, subArgs[1], subArgs[3]);
if (!this.preventDups || !this.getSubs(node, args,null,true)) {
handle = this._getNotifier(node, subArgs, extra,filter);
this[method](node, handle.sub, handle.notifier, filter);
handles.push(handle);
}
}
}, this);
return (handles.length === 1) ?
handles[0] :
new Y.EventHandle(handles);
},
/**
* Creates a new Notifier object for use by this event's
* <code>on(...)</code> or <code>delegate(...)</code> implementation.
*
* @method _getNotifier
* @param node {Node} the Node hosting the event
* @param args {Array} the subscription arguments passed to either
* <code>Y.on(...)</code> or <code>Y.delegate(...)</code>
* after running through <code>processArgs(args)</code> to
* normalize the argument signature
* @param extra {any} Extra data parsed from
* <code>processArgs(args)</code>
* @param filter {String|Function} the selector string or function
* filter passed to <code>Y.delegate(...)</code> (not
* present when called from <code>Y.on(...)</code>)
* @return {SyntheticEvent.Notifier}
* @private
* @since 3.2.0
*/
_getNotifier: function (node, args, extra, filter) {
var dispatcher = new Y.CustomEvent(this.type, this.publishConfig),
handle = dispatcher.on.apply(dispatcher, args),
notifier = new Notifier(handle, this.emitFacade),
registry = SyntheticEvent.getRegistry(node, this.type, true),
sub = handle.sub;
handle.notifier = notifier;
sub.node = node;
sub.filter = filter;
sub._extra = extra;
Y.mix(dispatcher, {
eventDef : this,
notifier : notifier,
host : node, // I forget what this is for
currentTarget: node, // for generating facades
target : node, // for generating facades
el : node._node, // For category detach
_delete : SyntheticEvent._deleteSub
}, true);
registry.push(handle);
return handle;
},
/**
* Removes the subscription from the Notifier registry.
*
* @method _unregisterSub
* @param sub {Subscription} the subscription
* @private
* @since 3.2.0
*/
_unregisterSub: function (sub) {
var notifiers = SyntheticEvent.getRegistry(sub.node, this.type),
i;
if (notifiers) {
for (i = notifiers.length - 1; i >= 0; --i) {
if (notifiers[i].sub === sub) {
notifiers.splice(i, 1);
break;
}
}
}
},
/**
* Removes the subscription(s) from the internal subscription dispatch
* mechanism. See <code>SyntheticEvent._deleteSub</code>.
*
* @method _detach
* @param args {Array} The arguments passed to
* <code>node.detach(...)</code>
* @private
* @since 3.2.0
*/
_detach: function (args) {
// Can't use Y.all because it doesn't support window (yet?)
// TODO: Does Y.all support window now?
var target = args[2],
els = (isString(target)) ?
query(target) : toArray(target),
node, i, len, handles, j;
// (type, fn, el, context, filter?) => (type, fn, context, filter?)
args.splice(2, 1);
for (i = 0, len = els.length; i < len; ++i) {
node = Y.one(els[i]);
if (node) {
handles = this.getSubs(node, args);
if (handles) {
for (j = handles.length - 1; j >= 0; --j) {
handles[j].detach();
}
}
}
}
},
/**
* 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.
*
* @method getSubs
* @param node {Node} the node hosting the event
* @param args {Array} the array of original subscription args passed
* to <code>Y.on(...)</code> (before
* <code>processArgs</code>
* @param filter {Function} function used to identify a subscription
* for inclusion in the returned array
* @param first {Boolean} stop after the first match (used to check for
* duplicate subscriptions)
* @return {Array} detach handles for the matching subscriptions
*/
getSubs: function (node, args, filter, first) {
var notifiers = SyntheticEvent.getRegistry(node, this.type),
handles = [],
i, len, handle;
if (notifiers) {
if (!filter) {
filter = this.subMatch;
}
for (i = 0, len = notifiers.length; i < len; ++i) {
handle = notifiers[i];
if (filter.call(this, handle.sub, args)) {
if (first) {
return handle;
} else {
handles.push(notifiers[i]);
}
}
}
}
return handles.length && handles;
},
/**
* <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>
*
* @method subMatch
* @param sub {Subscription} the existing subscription
* @param args {Array} the calling arguments passed to
* <code>Y.on(...)</code> etc.
* @return {Boolean} true if the sub can be described by the args
* present
* @since 3.2.0
*/
subMatch: function (sub, args) {
// Default detach cares only about the callback matching
return !args[1] || sub.fn === args[1];
}
}
}, true);
Y.SyntheticEvent = SyntheticEvent;
/**
* <p>Defines a new event in the DOM event system. Implementers are
* responsible for monitoring for a scenario whereby the event is fired. A
* notifier object is provided to the functions identified below. When the
* criteria defining the event are met, call notifier.fire( [args] ); to
* execute event subscribers.</p>
*
* <p>The first parameter is the name of the event. The second parameter is a
* configuration object which define the behavior of the event system when the
* new event is subscribed to or detached from. The methods that should be
* defined in this configuration object are <code>on</code>,
* <code>detach</code>, <code>delegate</code>, and <code>detachDelegate</code>.
* You are free to define any other methods or properties needed to define your
* event. Be aware, however, that since the object is used to subclass
* SyntheticEvent, you should avoid method names used by SyntheticEvent unless
* your intention is to override the default behavior.</p>
*
* <p>This is a list of properties and methods that you can or should specify
* in the configuration object:</p>
*
* <dl>
* <dt><code>on</code></dt>
* <dd><code>function (node, subscription, notifier)</code> The
* implementation logic for subscription. Any special setup you need to
* do to create the environment for the event being fired--E.g. native
* DOM event subscriptions. Store subscription related objects and
* state on the <code>subscription</code> object. When the
* criteria have been met to fire the synthetic event, call
* <code>notifier.fire(e)</code>. See Notifier's <code>fire()</code>
* method for details about what to pass as parameters.</dd>
*
* <dt><code>detach</code></dt>
* <dd><code>function (node, subscription, notifier)</code> The
* implementation logic for cleaning up a detached subscription. E.g.
* detach any DOM subscriptions added in <code>on</code>.</dd>
*
* <dt><code>delegate</code></dt>
* <dd><code>function (node, subscription, notifier, filter)</code> The
* implementation logic for subscription via <code>Y.delegate</code> or
* <code>node.delegate</code>. The filter is typically either a selector
* string or a function. You can use
* <code>Y.delegate.compileFilter(selectorString)</code> to create a
* filter function from a selector string if needed. The filter function
* expects an event object as input and should output either null, a
* matching Node, or an array of matching Nodes. Otherwise, this acts
* like <code>on</code> DOM event subscriptions. Store subscription
* related objects and information on the <code>subscription</code>
* object. When the criteria have been met to fire the synthetic event,
* call <code>notifier.fire(e)</code> as noted above.</dd>
*
* <dt><code>detachDelegate</code></dt>
* <dd><code>function (node, subscription, notifier)</code> The
* implementation logic for cleaning up a detached delegate subscription.
* E.g. detach any DOM delegate subscriptions added in
* <code>delegate</code>.</dd>
*
* <dt><code>publishConfig</code></dt>
* <dd>(Object) The configuration object that will be used to instantiate
* the underlying CustomEvent. See Notifier's <code>fire</code> method
* for details.</dd>
*
* <dt><code>processArgs</code></dt
* <dd>
* <p><code>function (argArray, fromDelegate)</code> Optional method
* to extract any additional arguments from the subscription
* signature. Using this allows <code>on</code> or
* <code>delegate</code> signatures like
* <code>node.on("hover", overCallback,
* outCallback)</code>.</p>
* <p>When processing an atypical argument signature, make sure the
* args array is returned to the normal signature before returning
* from the function. For example, in the "hover" example
* above, the <code>outCallback</code> needs to be <code>splice</code>d
* out of the array. The expected signature of the args array for
* <code>on()</code> subscriptions is:</p>
* <pre>
* <code>[type, callback, target, contextOverride, argN...]</code>
* </pre>
* <p>And for <code>delegate()</code>:</p>
* <pre>
* <code>[type, callback, target, filter, contextOverride, argN...]</code>
* </pre>
* <p>where <code>target</code> is the node the event is being
* subscribed for. You can see these signatures documented for
* <code>Y.on()</code> and <code>Y.delegate()</code> respectively.</p>
* <p>Whatever gets returned from the function will be stored on the
* <code>subscription</code> object under
* <code>subscription._extra</code>.</p></dd>
* <dt><code>subMatch</code></dt>
* <dd>
* <p><code>function (sub, args)</code> 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>
* </dd>
* </dl>
*
* @method Event.define
* @param type {String} the name of the event
* @param config {Object} the prototype definition for the new event (see above)
* @param force {Boolean} override an existing event (use with caution)
* @static
* @return {SyntheticEvent} the subclass implementation instance created to
* handle event subscriptions of this type
* @for Event
* @since 3.1.0
* @in event-synthetic
*/
Y.Event.define = function (type, config, force) {
if (!config) {
config = {};
}
var eventDef = (isObject(type)) ? type : Y.merge({ type: type }, config),
Impl, synth;
if (force || !Y.Node.DOM_EVENTS[eventDef.type]) {
Impl = function () {
SyntheticEvent.apply(this, arguments);
};
Y.extend(Impl, SyntheticEvent, eventDef);
synth = new Impl();
type = synth.type;
Y.Node.DOM_EVENTS[type] = Y.Env.evt.plugins[type] = {
eventDef: synth,
on: function () {
return synth._on(toArray(arguments));
},
delegate: function () {
return synth._on(toArray(arguments), true);
},
detach: function () {
return synth._detach(toArray(arguments));
}
};
}
return synth;
};