StringProperty

StringProperty (from scenerystack/axon) is a Property whose value must be a string. It adds no methods beyond Property<string> — its entire job is fixing valueType: 'string' and the PhET-iO StringIO type so every string-valued piece of simulation state validates and serializes consistently.

import { StringProperty } from 'scenerystack/axon';

const labelProperty = new StringProperty( 'Start' );

labelProperty.link( label => console.log( 'button label:', label ) );
labelProperty.value = 'Resume';

Options

StringPropertyOptions is PropertyOptions<string> with valueType and phetioValueType removed, since StringProperty sets both internally ('string' and StringIO, respectively). All other PropertyOptions — validValues, isValidValue, units, reentrant, etc. — pass through normally:

const modeProperty = new StringProperty( 'idle', {
  validValues: [ 'idle', 'running', 'paused' ]
} );

Role in localization

Displayed, translatable UI text in SceneryStack simulations is generally exposed through generated StringProperty instances (from the sim's -strings_en.json and Fluent-based string modules), not through this constructor directly — but the underlying contract is the same Property<string> API described here and on the Property page: .value, .link(), .dispose(). Any scenery Node that displays text (e.g. Text, RichText) accepts a TReadOnlyProperty<string> for its string/stringProperty option, so a plain StringProperty is a fine stand-in during development before the translated strings pipeline is wired up.

Restricting to a fixed set of strings

If a string Property should only ever hold one of a small, fixed set of values (e.g. 'idle' | 'running' | 'paused'), consider whether an EnumerationProperty backed by an EnumerationValue subclass is a better fit than a raw StringProperty with validValues — the enumeration gives you compile-time exhaustiveness checks that a string union does not.