File yui3/src/event-custom/js/event-target.js
/**
* Custom event engine, DOM event listener abstraction layer, synthetic DOM
* events.
* @module event-custom
* @submodule event-custom-base
*/
/**
* EventTarget provides the implementation for any object to
* publish, subscribe and fire to custom events, and also
* alows other EventTargets to target the object with events
* sourced from the other object.
* EventTarget is designed to be used with Y.augment to wrap
* EventCustom in an interface that allows events to be listened to
* and fired by name. This makes it possible for implementing code to
* subscribe to an event that either has not been created yet, or will
* not be created at all.
* @class EventTarget
* @param opts a configuration object
* @config emitFacade {boolean} if true, all events will emit event
* facade payloads by default (default false)
* @config prefix {String} the prefix to apply to non-prefixed event names
*/
var L = Y.Lang,
PREFIX_DELIMITER = ':',
CATEGORY_DELIMITER = '|',
AFTER_PREFIX = '~AFTER~',
WILD_TYPE_RE = /(.*?)(:)(.*?)/,
_wildType = Y.cached(function(type) {
return type.replace(WILD_TYPE_RE, "*$2$3");
}),
/**
* If the instance has a prefix attribute and the
* event type is not prefixed, the instance prefix is
* applied to the supplied type.
* @method _getType
* @private
*/
_getType = function(type, pre) {
if (!pre || (typeof type !== "string") || type.indexOf(PREFIX_DELIMITER) > -1) {
return type;
}
return pre + PREFIX_DELIMITER + type;
},
/**
* Returns an array with the detach key (if provided),
* and the prefixed event name from _getType
* Y.on('detachcategory| menu:click', fn)
* @method _parseType
* @private
*/
_parseType = Y.cached(function(type, pre) {
var t = type, detachcategory, after, i;
if (!L.isString(t)) {
return t;
}
i = t.indexOf(AFTER_PREFIX);
if (i > -1) {
after = true;
t = t.substr(AFTER_PREFIX.length);
}
i = t.indexOf(CATEGORY_DELIMITER);
if (i > -1) {
detachcategory = t.substr(0, (i));
t = t.substr(i+1);
if (t === '*') {
t = null;
}
}
// detach category, full type with instance prefix, is this an after listener, short type
return [detachcategory, (pre) ? _getType(t, pre) : t, after, t];
}),
ET = function(opts) {
var etState = this._yuievt,
etConfig;
if (!etState) {
etState = this._yuievt = {
events: {}, // PERF: Not much point instantiating lazily. We're bound to have events
targets: null, // PERF: Instantiate lazily, if user actually adds target,
config: {
host: this,
context: this
},
chain: Y.config.chain
};
}
etConfig = etState.config;
if (opts) {
mixConfigs(etConfig, opts, true);
if (opts.chain !== undefined) {
etState.chain = opts.chain;
}
if (opts.prefix) {
etConfig.prefix = opts.prefix;
}
}
};
ET.prototype = {
constructor: ET,
/**
* Listen to a custom event hosted by this object one time.
* This is the equivalent to <code>on</code> except the
* listener is immediatelly detached when it is executed.
* @method once
* @param {String} type The name of the event
* @param {Function} fn The callback to execute in response to the event
* @param {Object} [context] Override `this` object in callback
* @param {Any} [arg*] 0..n additional arguments to supply to the subscriber
* @return {EventHandle} A subscription handle capable of detaching the
* subscription
*/
once: function() {
var handle = this.on.apply(this, arguments);
handle.batch(function(hand) {
if (hand.sub) {
hand.sub.once = true;
}
});
return handle;
},
/**
* Listen to a custom event hosted by this object one time.
* This is the equivalent to <code>after</code> except the
* listener is immediatelly detached when it is executed.
* @method onceAfter
* @param {String} type The name of the event
* @param {Function} fn The callback to execute in response to the event
* @param {Object} [context] Override `this` object in callback
* @param {Any} [arg*] 0..n additional arguments to supply to the subscriber
* @return {EventHandle} A subscription handle capable of detaching that
* subscription
*/
onceAfter: function() {
var handle = this.after.apply(this, arguments);
handle.batch(function(hand) {
if (hand.sub) {
hand.sub.once = true;
}
});
return handle;
},
/**
* Takes the type parameter passed to 'on' and parses out the
* various pieces that could be included in the type. If the
* event type is passed without a prefix, it will be expanded
* to include the prefix one is supplied or the event target
* is configured with a default prefix.
* @method parseType
* @param {String} type the type
* @param {String} [pre] The prefix. Defaults to this._yuievt.config.prefix
* @since 3.3.0
* @return {Array} an array containing:
* * the detach category, if supplied,
* * the prefixed event type,
* * whether or not this is an after listener,
* * the supplied event type
*/
parseType: function(type, pre) {
return _parseType(type, pre || this._yuievt.config.prefix);
},
/**
* Subscribe a callback function to a custom event fired by this object or
* from an object that bubbles its events to this object.
*
* this.on("change", this._onChange, this);
*
* Callback functions for events published with `emitFacade = true` will
* receive an `EventFacade` as the first argument (typically named "e").
* These callbacks can then call `e.preventDefault()` to disable the
* behavior published to that event's `defaultFn`. See the `EventFacade`
* API for all available properties and methods. Subscribers to
* non-`emitFacade` events will receive the arguments passed to `fire()`
* after the event name.
*
* To subscribe to multiple events at once, pass an object as the first
* argument, where the key:value pairs correspond to the eventName:callback.
*
* this.on({
* "attrChange" : this._onAttrChange,
* "change" : this._onChange
* });
*
* You can also pass an array of event names as the first argument to
* subscribe to all listed events with the same callback.
*
* this.on([ "change", "attrChange" ], this._onChange);
*
* Returning `false` from a callback is supported as an alternative to
* calling `e.preventDefault(); e.stopPropagation();`. However, it is
* recommended to use the event methods whenever possible.
*
* @method on
* @param {String} type The name of the event
* @param {Function} fn The callback to execute in response to the event
* @param {Object} [context] Override `this` object in callback
* @param {Any} [arg*] 0..n additional arguments to supply to the subscriber
* @return {EventHandle} A subscription handle capable of detaching that
* subscription
*/
on: function(type, fn, context) {
var yuievt = this._yuievt,
parts = _parseType(type, yuievt.config.prefix), f, c, args, ret, ce,
detachcategory, handle, store = Y.Env.evt.handles, after, adapt, shorttype,
Node = Y.Node, n, domevent, isArr;
// full name, args, detachcategory, after
this._monitor('attach', parts[1], {
args: arguments,
category: parts[0],
after: parts[2]
});
if (L.isObject(type)) {
if (L.isFunction(type)) {
return Y.Do.before.apply(Y.Do, arguments);
}
f = fn;
c = context;
args = nativeSlice.call(arguments, 0);
ret = [];
if (L.isArray(type)) {
isArr = true;
}
after = type._after;
delete type._after;
Y.each(type, function(v, k) {
if (L.isObject(v)) {
f = v.fn || ((L.isFunction(v)) ? v : f);
c = v.context || c;
}
var nv = (after) ? AFTER_PREFIX : '';
args[0] = nv + ((isArr) ? v : k);
args[1] = f;
args[2] = c;
ret.push(this.on.apply(this, args));
}, this);
return (yuievt.chain) ? this : new Y.EventHandle(ret);
}
detachcategory = parts[0];
after = parts[2];
shorttype = parts[3];
// extra redirection so we catch adaptor events too. take a look at this.
if (Node && Y.instanceOf(this, Node) && (shorttype in Node.DOM_EVENTS)) {
args = nativeSlice.call(arguments, 0);
args.splice(2, 0, Node.getDOMNode(this));
// Y.log("Node detected, redirecting with these args: " + args);
return Y.on.apply(Y, args);
}
type = parts[1];
if (Y.instanceOf(this, YUI)) {
adapt = Y.Env.evt.plugins[type];
args = nativeSlice.call(arguments, 0);
args[0] = shorttype;
if (Node) {
n = args[2];
if (Y.instanceOf(n, Y.NodeList)) {
n = Y.NodeList.getDOMNodes(n);
} else if (Y.instanceOf(n, Node)) {
n = Node.getDOMNode(n);
}
domevent = (shorttype in Node.DOM_EVENTS);
// Captures both DOM events and event plugins.
if (domevent) {
args[2] = n;
}
}
// check for the existance of an event adaptor
if (adapt) {
Y.log('Using adaptor for ' + shorttype + ', ' + n, 'info', 'event');
handle = adapt.on.apply(Y, args);
} else if ((!type) || domevent) {
handle = Y.Event._attach(args);
}
}
if (!handle) {
ce = yuievt.events[type] || this.publish(type);
handle = ce._on(fn, context, (arguments.length > 3) ? nativeSlice.call(arguments, 3) : null, (after) ? 'after' : true);
// TODO: More robust regex, accounting for category
if (type.indexOf("*:") !== -1) {
this._hasSiblings = true;
}
}
if (detachcategory) {
store[detachcategory] = store[detachcategory] || {};
store[detachcategory][type] = store[detachcategory][type] || [];
store[detachcategory][type].push(handle);
}
return (yuievt.chain) ? this : handle;
},
/**
* subscribe to an event
* @method subscribe
* @deprecated use on
*/
subscribe: function() {
Y.log('EventTarget subscribe() is deprecated, use on()', 'warn', 'deprecated');
return this.on.apply(this, arguments);
},
/**
* Detach one or more listeners the from the specified event
* @method detach
* @param type {string|Object} Either the handle to the subscriber or the
* type of event. If the type
* is not specified, it will attempt to remove
* the listener from all hosted events.
* @param fn {Function} The subscribed function to unsubscribe, if not
* supplied, all subscribers will be removed.
* @param context {Object} The custom object passed to subscribe. This is
* optional, but if supplied will be used to
* disambiguate multiple listeners that are the same
* (e.g., you subscribe many object using a function
* that lives on the prototype)
* @return {EventTarget} the host
*/
detach: function(type, fn, context) {
var evts = this._yuievt.events,
i,
Node = Y.Node,
isNode = Node && (Y.instanceOf(this, Node));
// detachAll disabled on the Y instance.
if (!type && (this !== Y)) {
for (i in evts) {
if (evts.hasOwnProperty(i)) {
evts[i].detach(fn, context);
}
}
if (isNode) {
Y.Event.purgeElement(Node.getDOMNode(this));
}
return this;
}
var parts = _parseType(type, this._yuievt.config.prefix),
detachcategory = L.isArray(parts) ? parts[0] : null,
shorttype = (parts) ? parts[3] : null,
adapt, store = Y.Env.evt.handles, detachhost, cat, args,
ce,
keyDetacher = function(lcat, ltype, host) {
var handles = lcat[ltype], ce, i;
if (handles) {
for (i = handles.length - 1; i >= 0; --i) {
ce = handles[i].evt;
if (ce.host === host || ce.el === host) {
handles[i].detach();
}
}
}
};
if (detachcategory) {
cat = store[detachcategory];
type = parts[1];
detachhost = (isNode) ? Y.Node.getDOMNode(this) : this;
if (cat) {
if (type) {
keyDetacher(cat, type, detachhost);
} else {
for (i in cat) {
if (cat.hasOwnProperty(i)) {
keyDetacher(cat, i, detachhost);
}
}
}
return this;
}
// If this is an event handle, use it to detach
} else if (L.isObject(type) && type.detach) {
type.detach();
return this;
// extra redirection so we catch adaptor events too. take a look at this.
} else if (isNode && ((!shorttype) || (shorttype in Node.DOM_EVENTS))) {
args = nativeSlice.call(arguments, 0);
args[2] = Node.getDOMNode(this);
Y.detach.apply(Y, args);
return this;
}
adapt = Y.Env.evt.plugins[shorttype];
// The YUI instance handles DOM events and adaptors
if (Y.instanceOf(this, YUI)) {
args = nativeSlice.call(arguments, 0);
// use the adaptor specific detach code if
if (adapt && adapt.detach) {
adapt.detach.apply(Y, args);
return this;
// DOM event fork
} else if (!type || (!adapt && Node && (type in Node.DOM_EVENTS))) {
args[0] = type;
Y.Event.detach.apply(Y.Event, args);
return this;
}
}
// ce = evts[type];
ce = evts[parts[1]];
if (ce) {
ce.detach(fn, context);
}
return this;
},
/**
* detach a listener
* @method unsubscribe
* @deprecated use detach
*/
unsubscribe: function() {
Y.log('EventTarget unsubscribe() is deprecated, use detach()', 'warn', 'deprecated');
return this.detach.apply(this, arguments);
},
/**
* Removes all listeners from the specified event. If the event type
* is not specified, all listeners from all hosted custom events will
* be removed.
* @method detachAll
* @param type {String} The type, or name of the event
*/
detachAll: function(type) {
return this.detach(type);
},
/**
* Removes all listeners from the specified event. If the event type
* is not specified, all listeners from all hosted custom events will
* be removed.
* @method unsubscribeAll
* @param type {String} The type, or name of the event
* @deprecated use detachAll
*/
unsubscribeAll: function() {
Y.log('EventTarget unsubscribeAll() is deprecated, use detachAll()', 'warn', 'deprecated');
return this.detachAll.apply(this, arguments);
},
/**
* Creates a new custom event of the specified type. If a custom event
* by that name already exists, it will not be re-created. In either
* case the custom event is returned.
*
* @method publish
*
* @param type {String} the type, or name of the event
* @param opts {object} optional config params. Valid properties are:
* @param [opts.broadcast=false] {Boolean} whether or not the YUI instance and YUI global
* are notified when the event is fired.
* @param [opts.bubbles=true] {Boolean} Whether or not this event bubbles. Events can
* only bubble if `emitFacade` is true.
* @param [opts.context=this] {Object} the default execution context for the listeners.
* @param [opts.defaultFn] {Function} the default function to execute when this event
* fires if preventDefault was not called.
* @param [opts.emitFacade=false] {Boolean} whether or not this event emits a facade.
* @param [opts.prefix] {String} the prefix for this targets events, e.g., 'menu' in 'menu:click'.
* @param [opts.fireOnce=false] {Boolean} if an event is configured to fire once,
* new subscribers after the fire will be notified immediately.
* @param [opts.async=false] {Boolean} fireOnce event listeners will fire synchronously
* if the event has already fired unless `async` is `true`.
* @param [opts.preventable=true] {Boolean} whether or not `preventDefault()` has an effect.
* @param [opts.preventedFn] {Function} a function that is executed when `preventDefault()` is called.
* @param [opts.queuable=false] {Boolean} whether or not this event can be queued during bubbling.
* @param [opts.silent] {Boolean} if silent is true, debug messages are not provided for this event.
* @param [opts.stoppedFn] {Function} a function that is executed when stopPropagation is called.
* @param [opts.monitored] {Boolean} specifies whether or not this event should send notifications about
* when the event has been attached, detached, or published.
* @param [opts.type] {String} the event type (valid option if not provided as the first parameter to publish).
*
* @return {CustomEvent} the custom event
*
*/
publish: function(type, opts) {
var ret,
etState = this._yuievt,
etConfig = etState.config,
pre = etConfig.prefix;
if (typeof type === "string") {
if (pre) {
type = _getType(type, pre);
}
ret = this._publish(type, etConfig, opts);
} else {
ret = {};
Y.each(type, function(v, k) {
if (pre) {
k = _getType(k, pre);
}
ret[k] = this._publish(k, etConfig, v || opts);
}, this);
}
return ret;
},
/**
* Returns the fully qualified type, given a short type string.
* That is, returns "foo:bar" when given "bar" if "foo" is the configured prefix.
*
* NOTE: This method, unlike _getType, does no checking of the value passed in, and
* is designed to be used with the low level _publish() method, for critical path
* implementations which need to fast-track publish for performance reasons.
*
* @method _getFullType
* @private
* @param {String} type The short type to prefix
* @return {String} The prefixed type, if a prefix is set, otherwise the type passed in
*/
_getFullType : function(type) {
var pre = this._yuievt.config.prefix;
if (pre) {
return pre + PREFIX_DELIMITER + type;
} else {
return type;
}
},
/**
* The low level event publish implementation. It expects all the massaging to have been done
* outside of this method. e.g. the `type` to `fullType` conversion. It's designed to be a fast
* path publish, which can be used by critical code paths to improve performance.
*
* @method _publish
* @private
* @param {String} fullType The prefixed type of the event to publish.
* @param {Object} etOpts The EventTarget specific configuration to mix into the published event.
* @param {Object} ceOpts The publish specific configuration to mix into the published event.
* @return {CustomEvent} The published event. If called without `etOpts` or `ceOpts`, this will
* be the default `CustomEvent` instance, and can be configured independently.
*/
_publish : function(fullType, etOpts, ceOpts) {
var ce,
etState = this._yuievt,
etConfig = etState.config,
host = etConfig.host,
context = etConfig.context,
events = etState.events;
ce = events[fullType];
// PERF: Hate to pull the check out of monitor, but trying to keep critical path tight.
if ((etConfig.monitored && !ce) || (ce && ce.monitored)) {
this._monitor('publish', fullType, {
args: arguments
});
}
if (!ce) {
// Publish event
ce = events[fullType] = new Y.CustomEvent(fullType, etOpts);
if (!etOpts) {
ce.host = host;
ce.context = context;
}
}
if (ceOpts) {
mixConfigs(ce, ceOpts, true);
}
return ce;
},
/**
* This is the entry point for the event monitoring system.
* You can monitor 'attach', 'detach', 'fire', and 'publish'.
* When configured, these events generate an event. click ->
* click_attach, click_detach, click_publish -- these can
* be subscribed to like other events to monitor the event
* system. Inividual published events can have monitoring
* turned on or off (publish can't be turned off before it
* it published) by setting the events 'monitor' config.
*
* @method _monitor
* @param what {String} 'attach', 'detach', 'fire', or 'publish'
* @param eventType {String|CustomEvent} The prefixed name of the event being monitored, or the CustomEvent object.
* @param o {Object} Information about the event interaction, such as
* fire() args, subscription category, publish config
* @private
*/
_monitor: function(what, eventType, o) {
var monitorevt, ce, type;
if (eventType) {
if (typeof eventType === "string") {
type = eventType;
ce = this.getEvent(eventType, true);
} else {
ce = eventType;
type = eventType.type;
}
if ((this._yuievt.config.monitored && (!ce || ce.monitored)) || (ce && ce.monitored)) {
monitorevt = type + '_' + what;
o.monitored = what;
this.fire.call(this, monitorevt, o);
}
}
},
/**
* Fire a custom event by name. The callback functions will be executed
* from the context specified when the event was created, and with the
* following parameters.
*
* The first argument is the event type, and any additional arguments are
* passed to the listeners as parameters. If the first of these is an
* object literal, and the event is configured to emit an event facade,
* that object is mixed into the event facade and the facade is provided
* in place of the original object.
*
* If the custom event object hasn't been created, then the event hasn't
* been published and it has no subscribers. For performance sake, we
* immediate exit in this case. This means the event won't bubble, so
* if the intention is that a bubble target be notified, the event must
* be published on this object first.
*
* @method fire
* @param type {String|Object} The type of the event, or an object that contains
* a 'type' property.
* @param arguments {Object*} an arbitrary set of parameters to pass to
* the handler. If the first of these is an object literal and the event is
* configured to emit an event facade, the event facade will replace that
* parameter after the properties the object literal contains are copied to
* the event facade.
* @return {Boolean} True if the whole lifecycle of the event went through,
* false if at any point the event propagation was halted.
*/
fire: function(type) {
var typeIncluded = (typeof type === "string"),
argCount = arguments.length,
t = type,
yuievt = this._yuievt,
etConfig = yuievt.config,
pre = etConfig.prefix,
ret,
ce,
ce2,
args;
if (typeIncluded && argCount <= 3) {
// PERF: Try to avoid slice/iteration for the common signatures
// Most common
if (argCount === 2) {
args = [arguments[1]]; // fire("foo", {})
} else if (argCount === 3) {
args = [arguments[1], arguments[2]]; // fire("foo", {}, opts)
} else {
args = []; // fire("foo")
}
} else {
args = nativeSlice.call(arguments, ((typeIncluded) ? 1 : 0));
}
if (!typeIncluded) {
t = (type && type.type);
}
if (pre) {
t = _getType(t, pre);
}
ce = yuievt.events[t];
if (this._hasSiblings) {
ce2 = this.getSibling(t, ce);
if (ce2 && !ce) {
ce = this.publish(t);
}
}
// PERF: trying to avoid function call, since this is a critical path
if ((etConfig.monitored && (!ce || ce.monitored)) || (ce && ce.monitored)) {
this._monitor('fire', (ce || t), {
args: args
});
}
// this event has not been published or subscribed to
if (!ce) {
if (yuievt.hasTargets) {
return this.bubble({ type: t }, args, this);
}
// otherwise there is nothing to be done
ret = true;
} else {
if (ce2) {
ce.sibling = ce2;
}
ret = ce._fire(args);
}
return (yuievt.chain) ? this : ret;
},
getSibling: function(type, ce) {
var ce2;
// delegate to *:type events if there are subscribers
if (type.indexOf(PREFIX_DELIMITER) > -1) {
type = _wildType(type);
ce2 = this.getEvent(type, true);
if (ce2) {
ce2.applyConfig(ce);
ce2.bubbles = false;
ce2.broadcast = 0;
}
}
return ce2;
},
/**
* Returns the custom event of the provided type has been created, a
* falsy value otherwise
* @method getEvent
* @param type {String} the type, or name of the event
* @param prefixed {String} if true, the type is prefixed already
* @return {CustomEvent} the custom event or null
*/
getEvent: function(type, prefixed) {
var pre, e;
if (!prefixed) {
pre = this._yuievt.config.prefix;
type = (pre) ? _getType(type, pre) : type;
}
e = this._yuievt.events;
return e[type] || null;
},
/**
* Subscribe to a custom event hosted by this object. The
* supplied callback will execute after any listeners add
* via the subscribe method, and after the default function,
* if configured for the event, has executed.
*
* @method after
* @param {String} type The name of the event
* @param {Function} fn The callback to execute in response to the event
* @param {Object} [context] Override `this` object in callback
* @param {Any} [arg*] 0..n additional arguments to supply to the subscriber
* @return {EventHandle} A subscription handle capable of detaching the
* subscription
*/
after: function(type, fn) {
var a = nativeSlice.call(arguments, 0);
switch (L.type(type)) {
case 'function':
return Y.Do.after.apply(Y.Do, arguments);
case 'array':
// YArray.each(a[0], function(v) {
// v = AFTER_PREFIX + v;
// });
// break;
case 'object':
a[0]._after = true;
break;
default:
a[0] = AFTER_PREFIX + type;
}
return this.on.apply(this, a);
},
/**
* Executes the callback before a DOM event, custom event
* or method. If the first argument is a function, it
* is assumed the target is a method. For DOM and custom
* events, this is an alias for Y.on.
*
* For DOM and custom events:
* type, callback, context, 0-n arguments
*
* For methods:
* callback, object (method host), methodName, context, 0-n arguments
*
* @method before
* @return detach handle
*/
before: function() {
return this.on.apply(this, arguments);
}
};
Y.EventTarget = ET;
// make Y an event target
Y.mix(Y, ET.prototype);
ET.call(Y, { bubbles: false });
YUI.Env.globalEvents = YUI.Env.globalEvents || new ET();
/**
* Hosts YUI page level events. This is where events bubble to
* when the broadcast config is set to 2. This property is
* only available if the custom event module is loaded.
* @property Global
* @type EventTarget
* @for YUI
*/
Y.Global = YUI.Env.globalEvents;
// @TODO implement a global namespace function on Y.Global?
/**
`Y.on()` can do many things:
<ul>
<li>Subscribe to custom events `publish`ed and `fire`d from Y</li>
<li>Subscribe to custom events `publish`ed with `broadcast` 1 or 2 and
`fire`d from any object in the YUI instance sandbox</li>
<li>Subscribe to DOM events</li>
<li>Subscribe to the execution of a method on any object, effectively
treating that method as an event</li>
</ul>
For custom event subscriptions, pass the custom event name as the first argument
and callback as the second. The `this` object in the callback will be `Y` unless
an override is passed as the third argument.
Y.on('io:complete', function () {
Y.MyApp.updateStatus('Transaction complete');
});
To subscribe to DOM events, pass the name of a DOM event as the first argument
and a CSS selector string as the third argument after the callback function.
Alternately, the third argument can be a `Node`, `NodeList`, `HTMLElement`,
array, or simply omitted (the default is the `window` object).
Y.on('click', function (e) {
e.preventDefault();
// proceed with ajax form submission
var url = this.get('action');
...
}, '#my-form');
The `this` object in DOM event callbacks will be the `Node` targeted by the CSS
selector or other identifier.
`on()` subscribers for DOM events or custom events `publish`ed with a
`defaultFn` can prevent the default behavior with `e.preventDefault()` from the
event object passed as the first parameter to the subscription callback.
To subscribe to the execution of an object method, pass arguments corresponding to the call signature for
<a href="../classes/Do.html#methods_before">`Y.Do.before(...)`</a>.
NOTE: The formal parameter list below is for events, not for function
injection. See `Y.Do.before` for that signature.
@method on
@param {String} type DOM or custom event name
@param {Function} fn The callback to execute in response to the event
@param {Object} [context] Override `this` object in callback
@param {Any} [arg*] 0..n additional arguments to supply to the subscriber
@return {EventHandle} A subscription handle capable of detaching the
subscription
@see Do.before
@for YUI
**/
/**
Listen for an event one time. Equivalent to `on()`, except that
the listener is immediately detached when executed.
See the <a href="#methods_on">`on()` method</a> for additional subscription
options.
@see on
@method once
@param {String} type DOM or custom event name
@param {Function} fn The callback to execute in response to the event
@param {Object} [context] Override `this` object in callback
@param {Any} [arg*] 0..n additional arguments to supply to the subscriber
@return {EventHandle} A subscription handle capable of detaching the
subscription
@for YUI
**/
/**
Listen for an event one time. Equivalent to `once()`, except, like `after()`,
the subscription callback executes after all `on()` subscribers and the event's
`defaultFn` (if configured) have executed. Like `after()` if any `on()` phase
subscriber calls `e.preventDefault()`, neither the `defaultFn` nor the `after()`
subscribers will execute.
The listener is immediately detached when executed.
See the <a href="#methods_on">`on()` method</a> for additional subscription
options.
@see once
@method onceAfter
@param {String} type The custom event name
@param {Function} fn The callback to execute in response to the event
@param {Object} [context] Override `this` object in callback
@param {Any} [arg*] 0..n additional arguments to supply to the subscriber
@return {EventHandle} A subscription handle capable of detaching the
subscription
@for YUI
**/
/**
Like `on()`, this method creates a subscription to a custom event or to the
execution of a method on an object.
For events, `after()` subscribers are executed after the event's
`defaultFn` unless `e.preventDefault()` was called from an `on()` subscriber.
See the <a href="#methods_on">`on()` method</a> for additional subscription
options.
NOTE: The subscription signature shown is for events, not for function
injection. See <a href="../classes/Do.html#methods_after">`Y.Do.after`</a>
for that signature.
@see on
@see Do.after
@method after
@param {String} type The custom event name
@param {Function} fn The callback to execute in response to the event
@param {Object} [context] Override `this` object in callback
@param {Any} [args*] 0..n additional arguments to supply to the subscriber
@return {EventHandle} A subscription handle capable of detaching the
subscription
@for YUI
**/