How to optionally add timeout or onError on a Future chain?-CodePudding

I have a function with following code:

Future wrap(Future future, Duration? timeoutDuration) {
    return future.timeout(timeoutDuration).onError(handleError);
}

In some cases, I want to be able to skip adding a timeout, for e.g. when timeoutDuration is null. So, it should just be:

return future.onError(handleError);

One way to do this is to use if condition on nullability of timeoutDuration. But, this gets complicated if (in future; no pun) I want to do the same for onError when handleError is null. Here's my attempt:

Future wrap(Future future, Duration? timeoutDuration) {
  return _optionalErrorHandler(
    _optionalTimeout(future, timeoutDuration),
    () {},
  );
}

Future _optionalTimeout(Future future, Duration? timeoutDuration) {
  if (timeoutDuration == null) {
    return future;
  }

  return future.timeout(timeoutDuration);
}

Future _optionalErrorHandler(Future future, Function()? handler) { // handler: just for example
  if (handler == null) {
    return future;
  }

  return future.onError((error, stackTrace) => handler());
}

I want to ask if this is an optimal or recommended way to do this? Is there any inbuilt API that allows me to do this conditionally?

CodePudding user response：

Seems like a good use case for extensions.

extension FutureExt<T> on Future<T> {
  Future<T> timeoutNullable(Duration? timeLimit, {FutureOr<T> onTimeout()?}) {
    if (timeLimit != null) {
      return timeout(timeLimit, onTimeout: onTimeout);
    } else {
      return this;
    }
  }
}