TinyEmitter¶

Overview¶

Lightweight event & listener abstraction for a single event type.

@author Sam Reid (PhET Interactive Simulations) @author Michael Kauzmann (PhET Interactive Simulations)

Class TinyEmitter¶

import { TinyEmitter } from 'scenerystack/axon';

Constructor¶

new TinyEmitter( onBeforeNotify? : TinyEmitterOptions<T>['onBeforeNotify'] | null, hasListenerOrderDependencies? : TinyEmitterOptions<T>['hasListenerOrderDependencies'] | null, reentrantNotificationStrategy? : TinyEmitterOptions<T>['reentrantNotificationStrategy'] | null )¶

Instance Methods¶

dispose()¶

Disposes an Emitter. All listeners are removed.

emit( ...args : T )¶

Notify listeners

addListener( listener : TEmitterListener<T> )¶

Adds a listener which will be called during emit.

removeListener( listener : TEmitterListener<T> )¶

Removes a listener

removeAllListeners()¶

Removes all the listeners

hasListener( listener : TEmitterListener<T> ) : boolean¶

Checks whether a listener is registered with this Emitter

hasListeners() : boolean¶

Returns true if there are any listeners.

getListenerCount() : number¶

Returns the number of listeners.

forEachListener( callback : ( listener: TEmitterListener<T> ) => void )¶

Invokes a callback once for each listener - meant for Property's use

Instance Properties¶

changeCount : ( count: number ) => void¶

Not defined usually because of memory usage. If defined, this will be called when the listener count changes, e.g. changeCount( {number} listenersAddedQuantity ), with the number being negative for listeners removed.

isDisposed : boolean¶

Only defined when assertions are enabled - to keep track if it has been disposed or not

Source Code¶

See the source for TinyEmitter.ts in the axon repository.