Type Alias AddTypeDiscriminant<T, K>

AddTypeDiscriminant: T & { type: K }

Adds a type field to a type. Useful when creating discriminant union types.

type Base = { data: string };
type MyUnion = Discriminant<Base, 'base64'> | Discriminant<Base, 'hex'>;
const base64: MyUnion = { data: 'aGVsbG8=', type: 'base64' };
if (base64.type === 'base64') {
   console.log(base64.data);
}

Type Parameters

T
K extends string | number | symbol