TypeScript Types

In TypeScript, types are not 1:1 with their compile-time declarations. It's like Duck Typing. If an object has the right properties and methods it can be used as an instance of that type.

Utility Types

Types can be created from other Types, without having to redefine an entire Type.

Omit

Omit - create a Type from another Type with fewer properties.

interface Todo {
  title: string;
  description: string;
  completed: boolean;
  createdAt: number;
}
 
type TodoPreview = Omit<Todo, "description">;
 
const todo: TodoPreview = {
  title: "Clean room",
  completed: false,
  createdAt: 1615544252770,
};