StorableData
The in-memory shape of a namespace's contents, the type read and written through `Namespace`.
type StorableData<K extends string = string> = {
[key in K]: number | boolean | string | StorableData | StorableData[] | undefined | null | Date;
};This is the shape of a namespace's contents in memory — what you read and write through Namespace.
It is not the shape a save carries. In a saved game each value is tagged with its type so that a Date survives JSON, see SerializedNamespaceData.