Vector2Property

Vector2Property (from scenerystack/dot) is a Property<Vector2> subclass — the standard type for a model's positionProperty, a drag target's location, or any other Vector2-valued piece of observable state. Beyond fixing valueType: Vector2 and wiring up Vector2.Vector2IO for PhET-iO, it adds two validators of its own: it always rejects a vector with a NaN component, and it optionally confines every value to a Bounds2 region via the validBounds option.

import { Vector2Property } from 'scenerystack/dot';
import { Vector2, Bounds2 } from 'scenerystack/dot';

const positionProperty = new Vector2Property( new Vector2( 0, 0 ), {
  validBounds: new Bounds2( -100, -100, 100, 100 )
} );

positionProperty.link( position => console.log( 'position:', position ) );
positionProperty.value = new Vector2( 50, 50 ); // fine, inside validBounds
// positionProperty.value = new Vector2( 500, 0 ); // assertion failure: outside validBounds

Aside from these extra validators, Vector2Property behaves exactly like a plain Property<Vector2>: .value, .link(), .reset(), and every other member documented on Property work the same way.

Constructor

new Vector2Property( initialValue: Vector2, providedOptions?: Vector2PropertyOptions )

Vector2PropertyOptions is PropertyOptions<Vector2> (see Property's options) minus valueType/phetioValueType (which Vector2Property fixes for you), plus:

Option	Effect
validBounds	If provided, every value set on the Property must satisfy validBounds.containsPoint( value ); enforced via an assertion-only validator, so it has no effect in production builds without assertions

Mutating the stored Vector2 in place bypasses validation and listeners

Because Vector2Property's validators (including validBounds) only run inside set()/value=, calling a mutating method directly on the currently-stored vector — positionProperty.value.add( delta ) instead of positionProperty.value = positionProperty.value.plus( delta ) — skips both the bounds check and listener notification entirely. Always reassign .value with a new Vector2 (via plus, plusXY, etc.) rather than mutating the existing one in place; see the same caveat on Vector2.