Zero-Cost Nominales Typ-Branding über Einzigartige Symbol-Kapselung

declare const brandSymbol: unique symbol;
 
export type Brand<T, B extends string> = T & {
  readonly [brandSymbol]: B;
};
 
type UserId = Brand<string, "UserId">;
type OrderId = Brand<string, "OrderId">;
 
function createUserId(raw: string): UserId {
  if (!raw.startsWith("usr_")) throw new Error("Invalid User ID format");
  return raw as UserId;
}
 
function createOrderId(raw: string): OrderId {
  if (!raw.startsWith("ord_")) throw new Error("Invalid Order ID format");
  return raw as OrderId;
}
 
function fetchUserOrders(userId: UserId): void {
  console.log(`Fetching orders for user ${userId}`);
}
 
const validUser = createUserId("usr_9981");
fetchUserOrders(validUser);