Proposal:Type Pattern matching

[kgtkr]

example:

type NotNull=*|null;
type useNotNull=NotNull(number|null);//number;

type ListItem=List<*>;
type useListItem=ListItem(List<string>);//string;

type Constructor={new():*};
type useConstructor=Constructor({new():Date});//Date;

type FuncReturn=()=>*;
type useFuncReturn=FuncReturn(typeof Date.now);//number;

[kitsonk]

Can you explain how this differs to #19800, #16067 and #12424?

[ghost]

@rbuckton had a proposal for matched types that I can't seem to find.

[kgtkr]

sorry
Maybe duplicate #12424