Adding Error Verification for API Handlers in Effect Typescript Library

  .add(
    HttpApiEndpoint.get('abc', '/abc')
      .addSuccess(HttpApiSchema.NoContent)
      .addError(DataNotAvaiable)
      .addError(EndpointNotImplementedError)
  )

    handlers.handle('abc', () => Effect.succeed(null) )

    handlers.pipe(
      handleExact('abc', () =>
        Effect.gen(function* () {
          if (Math.random() > 0.5) {
            return yield* new EndpointNotImplementedError();
          }
          if (Math.random() > 0.5) {
            return yield* new DataNotAvaiable();
          }
          return;
        }),
      ),
    )

type Result<Handler, DeclaredErrors, Returns> = Handler extends (
  request: any,
) => Effect.Effect<any, infer ActualErrors, any>
  ? [DeclaredErrors] extends [ActualErrors] // <-- the actual check
    ? Returns
    : never
  : never;

export const handleExact =
  <
    E,
    Provides,
    R,
    Endpoints extends HttpApiEndpoint.Any,
    Name extends HttpApiEndpoint.Name<Endpoints>,
    R1,
    Handler extends HttpApiEndpoint.HandlerWithName<Endpoints, Name, E, R1>,
  >(
    name: Name,
    handler: Handler,
  ) =>
  (
    handlers: HttpApiBuilder.Handlers<E, Provides, R, Endpoints>,
  ): Result<
    Handler,
    H.HttpApiEndpoint.Error<H.HttpApiEndpoint.WithName<Endpoints, Name>>,
    ReturnType<typeof handlers.handle<Name, R1>>
  > => {
    // @ts-ignore
    return handlers.handle(name, handler);
  };