TypeScript Type Aliases

Type aliases give names to complex types.

  ## Basic
  
  ```ts
  type ID = number | string;
  let userId: ID = 101;
  ```
  
  ## Object alias
  
  ```ts
  type User = {
    id: ID;
    name: string;
  };
  ```
  
  ## Intersection
  
  ```ts
  type A = { a: number };
  type B = { b: number };
  type C = A & B;
  
  let obj: C = { a: 1, b: 2 };
  ```
  
  ## Type vs Interface
  - Type: unions, primitives
  - Interface: object shapes, extension
  
  ## Remember
  - Use type for flexibility
  - Combine with unions/intersections