Interfaces and types describe object shapes.
  
  ## Interface
  ```ts
  interface User {
    id: number;
    name: string;
    active: boolean;
  }
  ```
  
  Use it:
  ```ts
  const user: User = {
    id: 1,
    name: "Tom",
    active: true,
  };
  ```
  
  ## Type alias
  ```ts
  type Product = {
    id: number;
    price: number;
  };
  ```
  
  ## Differences (simple)
  - interface: extendable, good for objects
  - type: flexible, unions, primitives
  
  ## Union types
  ```ts
  type ID = number | string;
  
  let uid: ID = 10;
  uid = "A10";
  ```
  
  ## Remember
  - interfaces for object contracts
  - type for flexible compositions
  

Purpose: model real data shapes. Benefit: your objects become predictable and self-documented.

Interfaces and Type Aliases

Learn TypeScript for type-safe JavaScript development.

Interfaces and Type Aliases

Interface

Type alias

Differences (simple)

Union types

Remember

More on TypeScript

TypeScript: Type 'X' is Not Assignable to Type 'Y'

TypeScript Intro

Why TypeScript over JavaScript