Test your knowledge on TypeScript Type Aliases & Advanced Types II Quiz (Narrowing, Discriminated Unions, Nullable Types). This quiz contains 10 questions.
Level: Beginner
Topic: type-aliases-and-advanced-types-ii
Type alias vs value: what compiles?
Given the following TypeScript code, what happens?
```typescript
type UserId = string;
const id: UserId = "u_123";
console.log(UserId);
```