You can do some pretty powerful stuff with TypeScript types, so you could model it like this: https://www.typescriptlang.org/play?#code/C4TwDgpgBAysBOBLAd...

Funnily enough, I made something similar a couple of months ago, not as a replacement for a "nothing" value but as a quick-and-dirty object placeholder and black box for tracking function calls.

https://github.com/UQ-eLIPSE/kuro