I proposed a primitive for this in TypeScript a couple of years ago [1].
While I'm not entirely convinced myself whether it is worth the effort, it offers the ability to express "a number greater than 0". Using type narrowing and intersection types, open/closed intervals emerge naturally from that. Just check `if (a > 0 && a < 1)` and its type becomes `(>0)&(<1)`, so the interval (0, 1).
I also built a simple playground that has a PoC implementation: https://nikeee.github.io/typescript-intervals/