AccessibleSlider

AccessibleSlider (from scenerystack/sun) is a trait — a function that takes a Node subclass and returns a new class with slider-like keyboard/PDOM behavior mixed in — rather than a Node you instantiate directly. Slider (and through it, HSlider/VSlider) is defined as class Slider extends Sizable( AccessibleSlider( Node, 0 ) ); reach for AccessibleSlider yourself only if you're building a custom slider-like component from scratch that needs the same keyboard behavior Slider gets for free.

import { AccessibleSlider } from 'scenerystack/sun';
import { Node } from 'scenerystack/scenery';
import { Range } from 'scenerystack/dot';
import { NumberProperty, Property } from 'scenerystack/axon';

class MyCustomSliderNode extends AccessibleSlider( Node, 0 ) {
  public constructor( valueProperty: NumberProperty, range: Range ) {
    super( {
      valueProperty: valueProperty,
      enabledRangeProperty: new Property( range ),
      keyboardStep: 1,
      shiftKeyboardStep: 0.1,
      pageKeyboardStep: 10
    } );
    // ...add your own visual children and mouse/touch dragging here
  }
}

AccessibleSlider( Type, optionsArgPosition ) takes the base class to extend and the zero-indexed position of that class's constructor options argument (Slider passes 0 since its own constructor's options are the first argument after super()'s implicit args) — AccessibleSlider needs this so its DelayedMutate-based option handling can intercept the right argument.

Under the hood, AccessibleSlider mixes in AccessibleValueHandler (which does the bulk of the PDOM/aria-valuenow/aria-valuetext work shared with AccessibleNumberSpinner) and adds slider-specific startDrag/drag/endDrag hooks on top, named to match Slider's own drag terminology rather than AccessibleValueHandler's more generic startInput/onInput/endInput.

Behavior it adds

Interaction	Effect
Arrow keys (Left/Down, Right/Up)	Decrement/increment valueProperty by keyboardStep
Shift + arrow keys	Decrement/increment by shiftKeyboardStep (usually smaller)
Page Up / Page Down	Increment/decrement by pageKeyboardStep (usually larger)
Home / End	Jump to the range's minimum / maximum

Options (via AccessibleValueHandler)

Option	Effect
valueProperty	Required — the numeric Property this behavior reads and writes
enabledRangeProperty	Required — a TReadOnlyProperty<Range> clamping keyboard-driven changes
keyboardStep / shiftKeyboardStep / pageKeyboardStep	Step sizes for the interactions above
constrainValue	(value: number) => number, applied before the value is committed
startDrag / drag / endDrag	Hooks fired at each stage of an accessible ("virtual drag") interaction — same names Slider itself exposes
roundToStepSize	Round the value to a multiple of keyboardStep on ordinary key presses

You're almost always consuming this indirectly

Simulation code essentially never calls AccessibleSlider directly — it's documented here because Slider's own startDrag/drag/endDrag/keyboardStep-family options are actually implemented by this trait, so this is the page to check for the precise contract behind those options. Compare AccessibleNumberSpinner, the equivalent trait behind NumberSpinner.