EnabledComponent and EnabledProperty

EnabledProperty (from scenerystack/axon) is a thin BooleanProperty subclass that standardizes what an "enabled" Property looks like: it defaults tandem name-checking (it asserts, if instrumented, that its tandem is named enabledProperty), sets phetioFeatured: true, and supplies default phetioDocumentation. EnabledComponent is a small base class built on top of it — extend EnabledComponent (instead of hand-rolling public readonly enabledProperty = new BooleanProperty( true )) to get a consistent enabledProperty, enabled getter/setter, and disposal wired up automatically, with the same PhET-iO conventions every other EnabledComponent subclass follows.

import { EnabledComponent } from 'scenerystack/axon';

class Thruster extends EnabledComponent {
  public constructor() {
    super( { enabled: true } );
  }

  public fire(): void {
    if ( this.isEnabled() ) {
      // ... apply thrust
    }
  }
}

const thruster = new Thruster();
thruster.enabled = false;
thruster.isEnabled(); // false

EnabledComponent options

Option	Default	Effect
enabledProperty	null	Supply your own TReadOnlyProperty<boolean> instead of letting EnabledComponent create one (useful to share/derive enabled-ness from elsewhere); if provided, EnabledComponent does not own or dispose it
enabled	true	Initial value of the auto-created enabledProperty; ignored if enabledProperty is supplied
enabledPropertyOptions	null	Options forwarded to the auto-created EnabledProperty (e.g. phetioDocumentation); ignored if enabledProperty is supplied
phetioEnabledPropertyInstrumented	true	Whether the auto-created enabledProperty gets a PhET-iO tandem (options.tandem.createTandem( 'enabledProperty' )) or Tandem.OPT_OUT
tandem	—	Standard PhET-iO tandem, used to namespace the auto-created enabledProperty

Public API

Member	Effect
enabledProperty	The underlying TProperty<boolean> — either the one you supplied or an auto-created EnabledProperty
enabled (getter/setter)	Convenience accessor for enabledProperty.value
isEnabled()	Same as reading .enabled
dispose()	Disposes the auto-created enabledProperty (only if EnabledComponent created it — a caller-supplied enabledProperty is left alone)

GatedEnabledProperty and friends

If you need an enabledProperty whose value combines an internal ("self") flag with an external, PhET-iO-controllable gate, see GatedEnabledProperty (and the parallel GatedBooleanProperty/GatedVisibleProperty) — also exported from scenerystack/axon. Public fields exposing a gated result should be typed ReadOnlyProperty<boolean>, matching the general rule that anything not meant to be set directly from outside advertises ReadOnlyProperty, not Property.

Passing your own enabledProperty opts you out of ownership

If you supply enabledProperty yourself (rather than letting EnabledComponent construct one), EnabledComponent will neither instrument nor dispose it — that Property's lifecycle is entirely your responsibility. This is the usual way to make several related objects share one enabledProperty, but forgetting to dispose the shared Property yourself is a common leak.