attempt at a MockedService utility type

MockedService.ts

/* eslint-disable @typescript-eslint/no-unused-vars */
/* eslint-disable @typescript-eslint/no-explicit-any */
type IfAny<T, Y, N> = 0 extends 1 & T ? Y : N;
type IsAny<T, Y, N> = IfAny<T, Y, N>;

type TypeWithGeneric<T> = T[];

// eslint-disable-next-line @typescript-eslint/no-explicit-any
// type extractGeneric<Type> =
//   Type extends jest.MaybeMockedDeep<infer X, any[], any> ? X : never;

// eslint-disable-next-line @typescript-eslint/no-explicit-any
type JestMockAny = jest.Mock<any, any, any>;
// eslint-disable-next-line @typescript-eslint/no-explicit-any
type JestMockString = jest.Mock<string, number[], null>;

type IsJestMockAny<T extends jest.MockableFunction> = IsAny<
  ReturnType<T>,
  never,
  jest.MaybeMockedDeep<T>
>;

const fn = jest.fn<string, number[], any>();

const result = fn(1, 2, 3);

type A = IsJestMockAny<JestMockAny>;
type B = IsJestMockAny<JestMockString>;

const b: B = (a, b) => {};

export type MockedService<
  T extends Record<string | symbol | number, jest.MockableFunction>
> = {
  // https://stackoverflow.com/questions/78674994/is-there-way-to-say-but-doesnt-match-any-in-typescript/78675024#78675024
  [K in keyof T]: IsJestMockAny<T[K]>;
} & T;

type Foo = {
  getA: (a: string, b: string) => Promise<{ c: string }>;
  getB: (e: number, f: number) => Promise<{ g: string }>;
};

const mockedFoo: MockedService<Foo> = {
  getA: jest.fn().mockRejectedValue(new Error('not implemented')),

  // nb. The mock return values are not stricted enforced, if you
  // don't wrap with jest.mocked!
  getB: jest.fn()
};

function createMockedService<
  T extends Record<string | symbol | number, jest.MockableFunction>,
  V extends MockedService<T>
>(value: V) {
  return value;
}

createMockedService<Foo>({
  getA: jest.fn().mockRejectedValue(new Error('not implemented')),

  // nb. The mock return values are not stricted enforced, if you
  // don't wrap with jest.mocked!
  getB: jest.fn()
});

mockedFoo.getB(1, 2);