Version 3.18.0
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BaseObservable Class

Module: base-observable
Parent Module: base

Available since 3.8.0

Provides an augmentable implementation of lifecycle and attribute events for BaseCore.

Methods

_defAttrChangeFn

(
  • e
  • eventFastPath
)
private

Default function for attribute change events.

Parameters:

  • e EventFacade

    The event object for attribute change events.

  • eventFastPath Boolean

    Whether or not we're using this as a fast path in the case of no listeners or not

_defDestroyFn

(
  • e
)
protected

Default destroy event handler

Parameters:

_defInitFn

(
  • e
)
protected

Default init event handler

Parameters:

  • e EventFacade

    Event object, with a cfg property which refers to the configuration object passed to the constructor.

_fireAttrChange

(
  • attrName
  • subAttrName
  • currVal
  • newVal
  • opts
  • [cfg]
)
private

Utility method to help setup the event payload and fire the attribute change event.

Parameters:

  • attrName String

    The name of the attribute

  • subAttrName String

    The full path of the property being changed, if this is a sub-attribute value being change. Otherwise null.

  • currVal Any

    The current value of the attribute

  • newVal Any

    The new value of the attribute

  • opts Object

    Any additional event data to mix into the attribute change event's event facade.

  • [cfg] Object optional

    The attribute config stored in State, if already available.

_getFullType

(
  • type
)
String private

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.

Parameters:

  • type String

    The short type to prefix

Returns:

String:

The prefixed type, if a prefix is set, otherwise the type passed in

_getType

() private

If the instance has a prefix attribute and the event type is not prefixed, the instance prefix is applied to the supplied type.

_hasPotentialSubscribers

(
  • fullType
)
Boolean private

Parameters:

  • fullType String

    The fully prefixed type name

Returns:

Boolean:

Whether the event has potential subscribers or not

_initAttribute

() private

Initializes Attribute

_monitor

(
  • what
  • eventType
  • o
)
private

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.

Parameters:

  • what String

    'attach', 'detach', 'fire', or 'publish'

  • eventType String | CustomEvent

    The prefixed name of the event being monitored, or the CustomEvent object.

  • o Object

    Information about the event interaction, such as fire() args, subscription category, publish config

_parseType

() private

Returns an array with the detach key (if provided), and the prefixed event name from _getType Y.on('detachcategory| menu:click', fn)

_preInitEventCfg

(
  • config
)
private

Handles the special on, after and target properties which allow the user to easily configure on and after listeners as well as bubble targets during construction, prior to init.

Parameters:

  • config Object

    The user configuration object

_publish

(
  • fullType
  • etOpts
  • ceOpts
)
CustomEvent private

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.

Parameters:

  • fullType String

    The prefixed type of the event to publish.

  • etOpts Object

    The EventTarget specific configuration to mix into the published event.

  • ceOpts Object

    The publish specific configuration to mix into the published event.

Returns:

CustomEvent:

The published event. If called without etOpts or ceOpts, this will be the default CustomEvent instance, and can be configured independently.

_set

(
  • name
  • val
  • opts
)
Object protected chainable

Allows setting of readOnly/writeOnce attributes. See set for argument details.

Parameters:

  • name String

    The name of the attribute.

  • val Any

    The value to set the attribute to.

  • opts Object

    (Optional) Optional event data to be mixed into the event facade passed to subscribers of the attribute's change event.

Returns:

Object:

A reference to the host object.

_setAttrs

(
  • attrs
  • opts
)
Object protected chainable

Implementation behind the public setAttrs method, to set multiple attribute values.

Parameters:

  • attrs Object

    An object with attributes name/value pairs.

  • opts Object

    Properties to mix into the event payload. These are shared and mixed into each set

Returns:

Object:

A reference to the host object.

addTarget

(
  • o
)
chainable

Registers another EventTarget as a bubble target. Bubble order is determined by the order registered. Multiple targets can be specified.

Events can only bubble if emitFacade is true.

Included in the event-custom-complex submodule.

Parameters:

after

(
  • type
  • fn
  • [context]
  • [arg*]
)
EventHandle

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.

Parameters:

  • type String

    The name of the event

  • fn Function

    The callback to execute in response to the event

  • [context] Object optional

    Override this object in callback

  • [arg*] Any optional

    0..n additional arguments to supply to the subscriber

Returns:

EventHandle:

A subscription handle capable of detaching the subscription

before

()

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

Returns:

detach handle

bubble

(
  • evt
)
Boolean

Propagate an event. Requires the event-custom-complex module.

Parameters:

Returns:

Boolean:

the aggregated return value from Event.Custom.fire

destroy

() Base chainable

Destroy lifecycle method. Fires the destroy event, prior to invoking destructors for the class hierarchy.

Subscribers to the destroy event can invoke preventDefault on the event object, to prevent destruction from proceeding.

Returns:

Base:

A reference to this object

detach

(
  • type
  • fn
  • context
)
EventTarget

Detach one or more listeners the from the specified event

Parameters:

  • 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.

  • fn Function

    The subscribed function to unsubscribe, if not supplied, all subscribers will be removed.

  • 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)

Returns:

EventTarget:

the host

detachAll

(
  • 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.

Parameters:

  • type String

    The type, or name of the event

fire

(
  • type
  • arguments
)
Boolean

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.

Parameters:

  • type String | Object

    The type of the event, or an object that contains a 'type' property.

  • 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.

Returns:

Boolean:

True if the whole lifecycle of the event went through, false if at any point the event propagation was halted.

getEvent

(
  • type
  • prefixed
)
CustomEvent

Returns the custom event of the provided type has been created, a falsy value otherwise

Parameters:

  • type String

    the type, or name of the event

  • prefixed String

    if true, the type is prefixed already

Returns:

CustomEvent:

the custom event or null

getTargets

()

Returns an array of bubble targets for this object.

Returns:

EventTarget[]

init

(
  • config
)
Base chainable

Init lifecycle method, invoked during construction. Fires the init event prior to setting up attributes and invoking initializers for the class hierarchy.

Parameters:

  • config Object

    Object with configuration property name/value pairs

Returns:

Base:

A reference to this object

on

(
  • type
  • fn
  • [context]
  • [arg*]
)
EventHandle

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.

Parameters:

  • type String

    The name of the event

  • fn Function

    The callback to execute in response to the event

  • [context] Object optional

    Override this object in callback

  • [arg*] Any optional

    0..n additional arguments to supply to the subscriber

Returns:

EventHandle:

A subscription handle capable of detaching that subscription

once

(
  • type
  • fn
  • [context]
  • [arg*]
)
EventHandle

Listen to a custom event hosted by this object one time. This is the equivalent to on except the listener is immediatelly detached when it is executed.

Parameters:

  • type String

    The name of the event

  • fn Function

    The callback to execute in response to the event

  • [context] Object optional

    Override this object in callback

  • [arg*] Any optional

    0..n additional arguments to supply to the subscriber

Returns:

EventHandle:

A subscription handle capable of detaching the subscription

onceAfter

(
  • type
  • fn
  • [context]
  • [arg*]
)
EventHandle

Listen to a custom event hosted by this object one time. This is the equivalent to after except the listener is immediatelly detached when it is executed.

Parameters:

  • type String

    The name of the event

  • fn Function

    The callback to execute in response to the event

  • [context] Object optional

    Override this object in callback

  • [arg*] Any optional

    0..n additional arguments to supply to the subscriber

Returns:

EventHandle:

A subscription handle capable of detaching that subscription

parseType

(
  • type
  • [pre]
)
Array

Inherited from EventTarget: event-custom/js/event-target.js:168

Available since 3.3.0

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.

Parameters:

  • type String

    the type

  • [pre] String optional

    The prefix. Defaults to this._yuievt.config.prefix

Returns:

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

publish

(
  • type
  • opts
)
CustomEvent

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.

Parameters:

  • type String

    the type, or name of the event

  • opts Object

    optional config params. Valid properties are:

    • [broadcast=false] Boolean optional

      whether or not the YUI instance and YUI global are notified when the event is fired.

    • [bubbles=true] Boolean optional

      Whether or not this event bubbles. Events can only bubble if emitFacade is true.

    • [context=this] Object optional

      the default execution context for the listeners.

    • [defaultFn] Function optional

      the default function to execute when this event fires if preventDefault was not called.

    • [emitFacade=false] Boolean optional

      whether or not this event emits a facade.

    • [prefix] String optional

      the prefix for this targets events, e.g., 'menu' in 'menu:click'.

    • [fireOnce=false] Boolean optional

      if an event is configured to fire once, new subscribers after the fire will be notified immediately.

    • [async=false] Boolean optional

      fireOnce event listeners will fire synchronously if the event has already fired unless async is true.

    • [preventable=true] Boolean optional

      whether or not preventDefault() has an effect.

    • [preventedFn] Function optional

      a function that is executed when preventDefault() is called.

    • [queuable=false] Boolean optional

      whether or not this event can be queued during bubbling.

    • [silent] Boolean optional

      if silent is true, debug messages are not provided for this event.

    • [stoppedFn] Function optional

      a function that is executed when stopPropagation is called.

    • [monitored] Boolean optional

      specifies whether or not this event should send notifications about when the event has been attached, detached, or published.

    • [type] String optional

      the event type (valid option if not provided as the first parameter to publish).

Returns:

CustomEvent:

the custom event

removeTarget

(
  • o
)
chainable

Removes a bubble target

Parameters:

set

(
  • name
  • value
  • opts
)
Object chainable

Sets the value of an attribute.

Parameters:

  • name String

    The name of the attribute. If the current value of the attribute is an Object, dot notation can be used to set the value of a property within the object (e.g. set("x.y.z", 5)).

  • value Any

    The value to set the attribute to.

  • opts Object

    (Optional) Optional event data to be mixed into the event facade passed to subscribers of the attribute's change event. This can be used as a flexible way to identify the source of a call to set, allowing the developer to distinguish between set called internally by the host, vs. set called externally by the application developer.

Returns:

Object:

A reference to the host object.

setAttrs

(
  • attrs
  • opts
)
Object chainable

Sets multiple attribute values.

Parameters:

  • attrs Object

    An object with attributes name/value pairs.

  • opts Object

    Properties to mix into the event payload. These are shared and mixed into each set

Returns:

Object:

A reference to the host object.

subscribe

() deprecated

Inherited from EventTarget: event-custom/js/event-target.js:346

Deprecated: use on

subscribe to an event

unsubscribe

() deprecated

Inherited from EventTarget: event-custom/js/event-target.js:469

Deprecated: use detach

detach a listener

unsubscribeAll

(
  • type
)
deprecated

Inherited from EventTarget: event-custom/js/event-target.js:490

Deprecated: use detachAll

Removes all listeners from the specified event. If the event type is not specified, all listeners from all hosted custom events will be removed.

Parameters:

  • type String

    The type, or name of the event

Events

destroy

Lifecycle event for the destroy phase, fired prior to destruction. Invoking the preventDefault method on the event object provided to subscribers will prevent destruction from proceeding.

Subscribers to the "after" moment of this event, will be notified after destruction is complete (and as a result cannot prevent destruction).

Event Payload:

init

Lifecycle event for the init phase, fired prior to initialization. Invoking the preventDefault() method on the event object provided to subscribers will prevent initialization from occuring.

Subscribers to the "after" momemt of this event, will be notified after initialization of the object is complete (and therefore cannot prevent initialization).

Event Payload:

  • e EventFacade

    Event object, with a cfg property which refers to the configuration object passed to the constructor.