Version 3.18.1
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SyntheticEvent Class

Module: event-synthetic
Parent Module: event

Available since 3.1.0

Wrapper class for the integration of new events into the YUI event infrastructure. Don't instantiate this object directly, use Y.Event.define(type, config). See that method for details.

Properties that MAY or SHOULD be specified in the configuration are noted below and in the description of Y.Event.define.

Constructor

SyntheticEvent

(
  • cfg
)

Defined in event/js/synthetic.js:207

Available since 3.1.0

Parameters:

  • cfg Object

    Implementation pieces and configuration

Methods

_deleteSub

(
  • sub
)
private

Defined in event/js/synthetic.js:262

Available since 3.2.0

Alternate _delete() method for the CustomEvent object created to manage SyntheticEvent subscriptions.

Parameters:

  • sub Subscription

    the subscription to clean up

_detach

(
  • args
)
private

Defined in event/js/synthetic.js:580

Available since 3.2.0

Removes the subscription(s) from the internal subscription dispatch mechanism. See SyntheticEvent._deleteSub.

Parameters:

  • args Array

    The arguments passed to node.detach(...)

_init

() protected

Construction logic for the event.

_on

(
  • args
  • delegate
)
EventHandle private

Sets up the boilerplate for detaching the event and facilitating the execution of subscriber callbacks.

Parameters:

  • args Array

    array of arguments passed to Y.on(...) or Y.delegate(...)

  • delegate Boolean

    true if called from Y.delegate(...)

Returns:

EventHandle:

the detach handle for this subscription

_subscribe

(
  • node
  • method
  • args
  • extra
  • filter
)
EventHandle private

Defined in event/js/synthetic.js:503

Available since 3.2.0

Creates a new Notifier object for use by this event's on(...) or delegate(...) implementation and register the custom event proxy in the DOM system for cleanup.

Parameters:

  • node Node

    the Node hosting the event

  • method String

    "on" or "delegate"

  • args Array

    the subscription arguments passed to either Y.on(...) or Y.delegate(...) after running through processArgs(args) to normalize the argument signature

  • extra Any

    Extra data parsed from processArgs(args)

  • filter String | Function

    the selector string or function filter passed to Y.delegate(...) (not present when called from Y.on(...))

Returns:

applyArgExtras

(
  • extra
  • sub
)

Implementers MAY provide this method definition.

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 Y.on('xyz', fn, xtra, 'div') 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.

The default implementation adds the data extracted by processArgs to the subscription object as sub._extra.

Parameters:

  • extra Any

    Any extra data extracted from processArgs

  • sub Subscription

    the individual subscription

delegate

(
  • node
  • sub
  • notifier
  • filter
)

Defined in event/js/synthetic.js:392

Available since 3.2.0

Implementers SHOULD provide this method definition.

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

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 Y.delegate.compileFilter(filter).

Parameters:

  • node Node

    the node the subscription is being applied to

  • sub Subscription

    the object to track this subscription

  • notifier SyntheticEvent.Notifier

    call notifier.fire(..) to trigger the execution of the subscribers

  • 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.

detach

(
  • node
  • sub
  • notifier
)

Implementers SHOULD provide this method definition.

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

Parameters:

  • node Node

    the node the subscription was applied to

  • sub Subscription

    the object tracking this subscription

  • notifier SyntheticEvent.Notifier

    the Notifier used to trigger the execution of the subscribers

detachDelegate

(
  • node
  • sub
  • notifier
  • filter
)

Defined in event/js/synthetic.js:421

Available since 3.2.0

Implementers SHOULD provide this method definition.

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

Parameters:

  • node Node

    the node the subscription was applied to

  • sub Subscription

    the object tracking this subscription

  • notifier SyntheticEvent.Notifier

    the Notifier used to trigger the execution of the subscribers

  • 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.

getRegistry

(
  • node
  • type
  • create
)
Array protected static

Defined in event/js/synthetic.js:229

Available since 3.2.0

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.

Parameters:

  • node Node

    the node

  • type String

    the event

  • create Boolean

    create a registration entry to host a new array if one doesn't exist.

Returns:

getSubs

(
  • node
  • args
  • filter
  • first
)
EventHandle[]

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

Parameters:

  • node Node

    the node hosting the event

  • args Array

    the array of original subscription args passed to Y.on(...) (before processArgs

  • filter Function

    function used to identify a subscription for inclusion in the returned array

  • first Boolean

    stop after the first match (used to check for duplicate subscriptions)

Returns:

EventHandle[]:

detach handles for the matching subscriptions

on

(
  • node
  • sub
  • notifier
)

Implementers SHOULD provide this method definition.

Implementation logic for subscriptions done via node.on(type, fn) or Y.on(type, fn, target). 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 detach method. Typically these handles are added to the sub object. Also for SyntheticEvents that leverage a single DOM subscription under the hood, it is recommended to pass the DOM event object to notifier.fire(e). (The event name on the object will be updated).

Parameters:

  • node Node

    the node the subscription is being applied to

  • sub Subscription

    the object to track this subscription

  • notifier SyntheticEvent.Notifier

    call notifier.fire(..) to trigger the execution of the subscribers

processArgs

(
  • args
  • delegate
)
Any

Implementers MAY provide this method definition.

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

Implementations must remove extra arguments from the args list before returning. The required args for on() subscriptions are

[type, callback, target, context, argN...]

The required args for delegate() subscriptions are

[type, callback, target, filter, context, argN...]

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

Parameters:

  • args Array

    parmeters passed to Y.on(..) or Y.delegate(..)

  • delegate Boolean

    true if the subscription is from Y.delegate

Returns:

Any:

subMatch

(
  • sub
  • args
)
Boolean

Defined in event/js/synthetic.js:659

Available since 3.2.0

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 getSubs() with no arguments will return all subs.

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 Y.on(...) or node.detach(...) etc.

Parameters:

  • sub Subscription

    the existing subscription

  • args Array

    the calling arguments passed to Y.on(...) etc.

Returns:

Boolean:

true if the sub can be described by the args present

Properties

preventDups

Boolean

Implementers MAY override this property.

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 subMatch method. Setting this to true will impact performance for high volume events.

Default: false