MoleculeIO needs more specific stateSchema for atoms and atomicBonds

[samreid]

From https://github.com/phetsims/phet-io/issues/1774, MoleculeIO needs more specific stateSchema for atoms and atomicBonds. Specifically, create new IO Types rather than using ObjectLiteralIO.

[pixelzoom]

This issue is > 2 years old. @jbphet is this issue still relevant?

[jbphet]

Hey @samreid - there has been a lot of phet-io water under the bridge since you created this issue, and the GitHub history shows you as the author of Molecule.MoleculeIO. Could you please take a quick look at Molecule.MoleculeIO in the Molecule.js file, which is now in the greenhouse-effect repo, and let me know if this is still a relevant issue?

[samreid]

Yes, it still seems relevant. MoleculeIO has a schema listed like so:

Molecule.MoleculeIO = new IOType( 'MoleculeIO', {
  valueType: Molecule,
  toStateObject: molecule => molecule.toStateObject(),
  fromStateObject: Molecule.fromStateObject,
  stateSchema: {
    highElectronicEnergyState: BooleanIO,
    centerOfGravity: Vector2.Vector2IO,

    // TODO: https://github.com/phetsims/greenhouse-effect/issues/40 more specific schema
    atoms: ArrayIO( ObjectLiteralIO ),
    atomicBonds: ArrayIO( ObjectLiteralIO ),
    velocity: Vector2.Vector2IO,
    absorptionHysteresisCountdownTime: NumberIO,
    currentVibrationRadians: NumberIO,
    currentRotationRadians: NumberIO
  }
} );

The problem is that the atoms is just ArrayIO( ObjectLiteralIO) and atomicBonds is listed as ArrayIO( ObjectLiteralIO ). Ideally these would be more like:

    atoms: ArrayIO( Atom.AtomIO ),
    atomicBonds: ArrayIO( AtomicBond.AtomicBondIO ),

Where AtomIO and AtomicBondIO have the appropriate state schema listings. Having the correct type here will help with runtime validation, code maintainability and possible future migration. Either @zepumph or I would be happy to collaborate with you if you wish.

[jbphet]

Thanks for the update @samreid.

I'm going to defer this issue. I just checked the published phet-io version of this sim at https://phet-io.colorado.edu/sims/molecules-and-light/1.3/wrappers/index/, and it looks quite old. The "Studio" wrapper isn't shown, which has been around for a long time now. I expect that there will be a moment in the future when this sim needs a full phet-io update, so I'll defer until that time. It just doesn't seem like it would be worth the time and effort to fix this up now.