assertNever

Callable

• assertNever<V>(subject: V): V

---

• Raise a compile error when accessing this function and throws a TypeError at runtime This is useful for exhaustive switch check.

  @example

  const print = (fruit: 'banana'|'kiwi') => {
    switch (fruit) {
      case 'banana': return '🍌 Banana';
      case 'kiwi': return '🥝 Kiwi';
      default: return assertNever(fruit); // <- This line will report an error if a case is missing
    }
  }

  ---

  Type parameters

  • V: never