These

These<E, A> = Err<E> | Ok<A> | Both<E, A>

These<E, A> is an inclusive-OR type: it holds an error value (E), a success value (A), or both simultaneously. It reuses Ok and Err from Result, adding a third Both<E, A> variant for partial success with a warning/error.

Err(e) — only an error/warning (no success value)
Ok(a) — only a success value (no error)
Both(e, a) — a warning together with a success value

Type Parameters

E

E

A

A

Example

const parse = (s: string): These<string, number> => {
  const n = parseFloat(s.trim());
  if (isNaN(n)) return These.err("Not a number");
  if (s !== s.trim()) return These.both("Leading/trailing whitespace trimmed", n);
  return These.ok(n);
};