CODEWITHSUNDEEP
typescript
LidorA
LidorA

Reputation: 667

Declare a type in TypeScript that denotes the empty set

I know a little about TypeScript which I've learned this month in a university course.

Can this denote the empty set?

type emptySet=0&1;

because when I try to assign this to any value, i.e. (boolean, number, string) I get type error.

I'm not sure what 0&1 does in typescript, in other programming languages, This denotes "false" or a bitwise operation.

Upvotes: 0

Views: 5016

Answers (2)

Rodris
Rodris

Reputation: 2858

The type that accepts nothing is void.

type emptySet = void;

let es: emptySet = null;

There is also the never type, which doesn't accept anything, even null.

type emptySet = never;

let es: emptySet = null; // Error

Upvotes: 0

Hampus
Hampus

Reputation: 2799

I'm not sure what you are trying to achieve but this is valid and would mean "empty set" as nothing can be void

type EmptySet = void[];

const empty: EmptySet = []; // valid
const notEmpty: EmptySet = [1,2,3]; // not valid

Upvotes: 1

Related Questions