OneOf.Chaining 1.4.0

dotnet add package OneOf.Chaining --version 1.4.0
NuGet\Install-Package OneOf.Chaining -Version 1.4.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="OneOf.Chaining" Version="1.4.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add OneOf.Chaining --version 1.4.0
#r "nuget: OneOf.Chaining, 1.4.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install OneOf.Chaining as a Cake Addin
#addin nuget:?package=OneOf.Chaining&version=1.4.0

// Install OneOf.Chaining as a Cake Tool
#tool nuget:?package=OneOf.Chaining&version=1.4.0


Extension methods which enable method chaining in C#, using the excellent OneOf library.

Turn this:

public async Task<OneOf<WeatherReport, Failure>> Handle(string requestedRegion, DateTime requestedDate)
	var isValidRequest = await regionValidator.Validate(requestedRegion);
	if (!isValidRequest)
		return new UnsupportedRegionFailure();

	var dateCheckPassed = await dateChecker.CheckDate(requestedDate);
	if (!dateCheckPassed)
		return new InvalidRequestFailure();

	var cacheCheckResult = CheckCache(requestedRegion, requestedDate);
	if (cacheCheckResult.Hit)
		return cacheCheckResult.Data;
		return weatherForecastGenerator.Generate(requestedRegion, requestedDate);

into this:

public async Task<OneOf<WeatherReport, Failure>> Handle(string requestedRegion, DateTime requestedDate)
	return await WeatherReport.Create(requestedRegion, requestedDate)
		.IfThen(report => report.PopulatedFromCache is false, 

For an explanation, see my blog post here or on ClearBank's Medium publication here


  • Then() which enables fluent chaining of any method which returns a Task<OneOf<Tsuccess, Tfailure>>.
  • Overload of Then() which takes an onFailure func, useful for tidying up previous tasks. Also able to mutate the Tfailure result.
  • IfThen() which takes a func of Tsuccess and bool, which should return true in order to invoke the nextJob.
  • ThenWaitForAll() and ThenWaitForFirst() methods which accept a list of tasks to be executed in parallel.
  • Versions of all extension methods with Cancellation support
Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.1 is compatible. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.
  • .NETStandard 2.1

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
1.4.0 1,246 4/1/2024
1.3.0 162 1/22/2024
1.2.0 373 11/15/2023
1.1.0 4,158 10/31/2023
1.0.0 128 9/26/2023

1.4.0) Added versions of the extension methods with Cancellation support, plus ThenForEach()
1.3.0) Package updates and fixed bug where OnFailure could return a TSuccess causing subsequent chained methods to run despite the previous Failure.
1.2.0) Package updates and targeting netstandard2.1 and embedded symbols in package for ease of debugging
1.1.0) Added parallel ThenWaitForAll and ThenWaitForFirst methods
1.0.0) initial version