Function get

tests/instance-of.test.ts:13–23

(x: A | B)

describe('instanceOf', () => {
  it('should work at the top level', () => {
    const get = (x: A | B): string =>
      match(x)
        .with(P.instanceOf(A), (x) => {
          type t = Expect<Equal<typeof x, A>>;
          return 'instance of A';
        })
        .with(P.instanceOf(B), (x) => {
          type t = Expect<Equal<typeof x, B>>;
          return 'instance of B';
        })
        .exhaustive();

    expect(get(new A())).toEqual('instance of A');
    expect(get(new B())).toEqual('instance of B');