[app-state]: Feature request: `PersistedStore`

[eric-simonton-sama]

It's a common pattern to combine a RootStore, Persistence and MigrationManager. It would be nice to reduce a little boilerplate. Something like:

export class PersistedStore<T extends VersionedObject> extends RootStore<T> {
  constructor(
    persistenceKey: string,
    defaultState: T,
    migrator: MigrationManager<T>,
  ) {
    const persistence = new Persistence<T>(persistenceKey);
    super(migrator.run(persistence, defaultState));

    this.$.subscribe((state) => persistence.put(state));
  }
}

[ersimont]

Added. Will be available in the next release.