Class UnexpectedValueError

Error class that produces a compile-time error if cases for a value weren’t covered exhaustively (e.g. via switch).

enum Color { Red, Green }
function colorToString(color: Color) {
  switch (color) {
    case Color.Red:
      return 'RED';
    default:
      // @ts-expect-error: Argument of type 'Color.Green' is not
      // assignable to parameter of type 'never'.
      throw new UnexpectedValueError(color);
  }
}
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