CODEWITHSUNDEEP
javascripttypescript
xipper
xipper

Reputation: 211

Typescript Pick multiple keys

interface A{
  a:{
    name: string
  }
  b:{
    age: number
  }
}

type PickMultiple = ..... //todo

const child:PickMultiple<A,['a','b']> = {
   name: 'mike',
   age: 18
}

How can I extract multiple keys? it was same as Pick Child key

Ofcourse Pick<A, 'a'| 'b'> can't work as expected

Upvotes: 12

Views: 19542

Answers (4)

Keith
Keith

Reputation: 24201

You might be over complicating this.

Update:

Like pointed out in the comments by ' Sebastien H', my original answer was not totally correct, it was basically saying a or b, and due to duck typing having both works too. So to make this stricter you need intersection type, not a union type.

How about..

interface A{
  a:{
    name: string
  }
  b:{
    age: number
  }
}

const child: A['a'] & A['b']= {
  name: 'Mike',
  age: 23,
}

With the original A['a' | 'b'] it would allow either name or age to be left out.

ps. Doing A['a' & 'b'] would also not be a shortcut here.

Upvotes: 3

marcobiedermann
marcobiedermann

Reputation: 4915

You can actually pick multiple keys by default

interface A {
  a: {
    name: string;
  };
  b: {
    age: number;
  };
}

type Picked = Pick<A, 'a' | 'b'>;

See full documentation: https://www.typescriptlang.org/docs/handbook/utility-types.html#picktype-keys

Upvotes: 4

xipper
xipper

Reputation: 211

interface A {
  a: {
    name: string
  }
  b: {
    age: number
  }
}

type Picked<T, K extends keyof T> = T[K]

const a: Picked<A, 'a' | 'b'> = {
  name: '1',
  age: 18,
}
console.log(a)

Upvotes: 9

Vladyslav Lazutkin
Vladyslav Lazutkin

Reputation: 211

It already supports multiple keys

interface Todo {
  title: string;
  description: string;
  completed: boolean;
}
 
type TodoPreview = Pick<Todo, "title" | "completed">;

Upvotes: 21

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