NBTObject should accept undefined values, which means NBT.stringify would omit them just as JSON.stringify does.
For the motivation, see this minimal example. This is a niche case, but there isn't really a clean workaround for it without removing type safety.
Additionally, I don't see any practical reason to disallow undefined. I can think of a few other (equally niche) cases where doing so would be problematic as well.
NBTObjectshould acceptundefinedvalues, which meansNBT.stringifywould omit them just asJSON.stringifydoes.For the motivation, see this minimal example. This is a niche case, but there isn't really a clean workaround for it without removing type safety.
Additionally, I don't see any practical reason to disallow
undefined. I can think of a few other (equally niche) cases where doing so would be problematic as well.