How to strengthen primitive type checking in TypeScript?

Question

typescript

Let's admit at me primitive types are used in different places. In order not to complicate my life by creating classes, but at the same time, in order to be able to have static typing, I would like to specify the string type. Unfortunately, TypeScript doesn't check in any way that the type is valid. Tell me, is it possible to do what I aspire to and how?

type IFooIndex = string;
type IBarIndex = string;

class Foo {
    id: IFooIndex;
}

class Bar {
    id: IBarIndex;
}

function findFoo(index: IFooIndex) {
    // searching by IFooIndex
}

findFoo( new Bar().id ); // тут хотелось бы ошибку компиляции

Answer 1

Branding to help you

type IFooIndex = string & {_type?: 'foo'};
type IBarIndex = string & {_type?: 'bar'};

class Foo {
    id: IFooIndex;
}

class Bar {
    id: IBarIndex;
}

function findFoo(index: IFooIndex) {
    // searching by IFooIndex
}

findFoo( new Bar().id );