In type theory, a theory within mathematical logic, the bottom type is the type that has no values. It is also called the zero or empty type, and is sometimes denoted with the up tack (⊥) symbol.
The "bottomest" types I can think of in js are
null, both unity types.
Notice how in TypeScript there is the explicit
never bottom type for function that are not supposed to return anything, or to always throw an exception.
The question is/are:
- if so, does that mean that languages do not need to have a bottom type?