CombineDriver
Drivers are Publishers which don't complete. CombineDriver is a small library which implements them for Apple's Combine.
Motivation:
Some data sources like user input do not logically 'complete' and modelling them with that in mind is semantically correct and sometimes practically preferable.
In particular the 'driving' logic in an application is often written assuming it will be robust to error states and will never finish on its own. suppressFinishToAnyDriver() enforces the lack of error states and prevents completion.
Usage
- Include the library via Swift Package Manager.
- Import
CombineDriver - Call
suppressFinishToAnyDriver()on aPublisherof failure typeNeverto receive anAnyDriverwhich has the aforementioned properties. - If desired:
- Use
suppressFailureAndFinishToAnyDriver()to also ignore failures from aPublisher. - Use
PassthroughDrivingSubjectandCurrentValueDrivingSubjectas alternatives to the native Combine Subjects.
- Use
Implementation:
The underlying implementation is simple:
extension Publisher {
/// suppressFailure prevents failures from emitting to subscribers.
func suppressFailure()
-> Publishers.CompactMap<Publishers.ReplaceError<Publishers.Map<Self, Self.Output?>>, Self.Output>
{
self
.map { Optional($0) }
.replaceError(with: nil)
.compactMap { $0 }
}
/// suppressCompletion prevents a completion from emitting to subscribers.
func suppressCompletion()
-> Publishers.FlatMap<Self, Publishers.SetFailureType<Publishers.Concatenate<Publishers.Sequence<[()], Never>, Empty<(), Never>>, Self.Failure>>
{
Empty(completeImmediately: false)
.prepend(())
.setFailureType(to: Failure.self)
.flatMap {
self
}
}
}
Future Improvements:
Convenience wrappers around use input sources in UIKit would probably be nice!
Contributions and super welcome.
543 Oct 29, 2022
2 Aug 27, 2022
83 Jan 6, 2023
18 Nov 14, 2022
553 Dec 29, 2022
2 Oct 28, 2022
2 Nov 3, 2021
1.1k Sep 29, 2022
0 Dec 23, 2021
1 Jan 29, 2022
1 Jan 27, 2022
40 Dec 10, 2022
46 Dec 24, 2022
43 Feb 9, 2022
20 Aug 4, 2022
2.6k Dec 29, 2022
3 Feb 22, 2022
7 Jul 20, 2022
121 Aug 11, 2022
3 Oct 12, 2022
8 Nov 3, 2022
4 Jul 20, 2022
11 Aug 25, 2022
6 Sep 26, 2022
53 Dec 11, 2021
156 Aug 31, 2022