TypeScript: Pick VS Record

ts_pick-vs-record.ts

// Definition of types

type Pick<T, K extends keyof T> = {
    [P in K]: T[P];
}

type Record<K extends string, T> = {
    [P in K]: T;
}


// PICK

interface Dog {
  id?: number;
  name: string;
  weight: number;
  age: number;
}

type Doggy = Pick<Dog, 'id' | 'name' >;

// is equivalent to 
type Doggy = {
  id?: number;
  name: string;
}


// RECORD

type ThreeDogProps = Record<'prop1' | 'prop2' | 'prop3', Dog>;

// is equivalent to 
type ThreeDogProps = {
  prop1: Dog;
  prop2: Dog;
  prop3: Dog;
}