Control Flow · hard

47. Exhaustive Never Check

Ensuring every case is handled in a switch.

Implement `check(s: 'a' | 'b')` that uses `never` in the default case.

Required in your answer: const _n: never = s

Transpiled, then run in a sandbox

function check(s: 'a' | 'b') {
  switch(s) {
    case 'a': return 1;
    case 'b': return 2;
    default: const _n: never = s; return _n;
  }
}

Output appears here.