resource_result 0.0.6

A package that provides a Resource class of any type. Supports the states Success, Failure and Loading.

Provides a Resource class containing data of any type and an error of any type. This allows methods to return a Resource<T> which can be a Success, Loading or Failure instead of returning a T and throwing an Exception if the method fails. Additionally, if a method returns a Future or Stream the Loading state can initially be returned.

Usage

To return a resource from a method:

Synchronous

Resource<int> parseInt(String value) {
  try {
    return Success(int.parse(value));
  } catch (e) {
    return Failure.fromMessage("Failed to parse value '$value'");
  }
}

Asynchronous

convert(someStream).listen((resource) {
    resource.resolve(
        onSuccess: (someClassData) => Text(
            "Converted someClass to otherClass instance successfully: $someClassData"),
        onLoading: (_) => Text("Loading..."),
        onFailure: (error) => Text("Failed to convert: $error")
    );
});

Use Resource result

final Resource<int> result = parseInt("13");
if (result.hasData) {
  Text("Parsed int successfully: ${result.data}");
} else {
  Text("Failed to parse int: ${result.error?.message}");
}
//or
Stream<Resource<OtherClass>> convert(Stream<SomeClass> toConvert) async* {
  yield Loading(EmptyOtherClass());
  await for (final someObject in toConvert) {
    try {
      final OtherClass converted = convertToSomeObject(someObject);
      yield Success(converted);
    } catch (e) {
      yield Failure.fromMessage("Failed convert '$someObject'");
    }
  }
}