Should Node visibleProperty be IReadOnlyProperty<boolean> ?

[pixelzoom]

In Geometric Optics, many of my visibleProperty instances are DerivedProperty. But I've noticed that when I pass them to Node, declaring them as IReadOnlyProperty<boolean causes a typescript error, complaining that IReadOnlyProperty does not implement set.

In Node.ts:

  visibleProperty?: IProperty<boolean> | null,

But Node works with a DerivedProperty for visibleProperty, whose set method is:

  set( value: T ): void {
    throw new Error( `Cannot set values directly to a DerivedProperty, tried to set: ${value}` );
  }

So I'm guessing that visibleProperty should really be:

  visibleProperty?: IReadOnlyProperty<boolean> | null,

[samreid]

Node's option is now visibleProperty?: TReadOnlyProperty<boolean> | null;, closing.