FsToolkit.ErrorHandling 5.0.0-beta011

.NET 9.0 This package targets .NET 9.0. The package is compatible with this framework or higher. .NET Standard 2.0 This package targets .NET Standard 2.0. The package is compatible with this framework or higher.
This is a prerelease version of FsToolkit.ErrorHandling. 
dotnet add package FsToolkit.ErrorHandling --version 5.0.0-beta011
                    


                    

                
NuGet\Install-Package FsToolkit.ErrorHandling -Version 5.0.0-beta011
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="FsToolkit.ErrorHandling" Version="5.0.0-beta011" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="FsToolkit.ErrorHandling" Version="5.0.0-beta011" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="FsToolkit.ErrorHandling" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add FsToolkit.ErrorHandling --version 5.0.0-beta011
                    


                    

                
#r "nuget: FsToolkit.ErrorHandling, 5.0.0-beta011"
#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. 
#addin nuget:?package=FsToolkit.ErrorHandling&version=5.0.0-beta011&prerelease
                    


                            Install FsToolkit.ErrorHandling as a Cake Addin
                        

                    

                
#tool nuget:?package=FsToolkit.ErrorHandling&version=5.0.0-beta011&prerelease
                    


                            Install FsToolkit.ErrorHandling as a Cake Tool

FsToolkit.ErrorHandling

FsToolkit.ErrorHandling is a utility library to work with the Result type in F#, and allows you to do clear, simple and powerful error handling.

The library provides utility functions like map, bind, apply, traverse, sequence as well as computation expressions and infix operators to work with Result<'a, 'b>, Result<'a option, 'b>, Async<Result<'a, 'b>>, Async<Result<'a option, 'b>>, and Result<'a, 'b list>.

It was inspired by Chessie and Cvdm.ErrorHandling (the latter has now been merged into FsToolkit.ErrorHandling).

FsToolkit.ErrorHandling targets .NET Standard 2.0, .NET Standard2.1 and supports Fable.

Documentation

The documentation is available here.

Further material

Builds

GitHub Actions
GitHub Actions
Build History

NuGet

Package name Release Prelease
FsToolkit.ErrorHandling NuGet NuGet
FsToolkit.ErrorHandling.TaskResult NuGet NuGet
FsToolkit.ErrorHandling.JobResult NuGet NuGet
FsToolkit.ErrorHandling.AsyncSeq NuGet NuGet
FsToolkit.ErrorHandling.IcedTasks NuGet NuGet

Developing locally

Devcontainer

This repository has a devcontainer setup for VSCode. For more information see:

Local Setup

Optional

To test fable builds locally you will need:

  • Node
    • v18.0.0 or Higher
    • Not required but recommend that you use NVM to easily manage multiple versions of Node
  • Python
    • v3.10.0 or higher
    • Required for Fable-Python
Compiling
> build.cmd <optional buildtarget> // on windows
$ ./build.sh  <optional buildtarget>// on unix

Without specifying a build target, the default target is DotnetPack, which will run tests for all projects on dotnet and then pack the projects into nuget packages. For additional notable targets see below.

Build Targets
  • Clean - Will clean all projects bin and obj folders
  • DotnetTest - Will run tests for dotnet projects
  • NpmTest - Will run tests for fable-javascript projects
  • PythonTest - Will run tests for fable-python projects
  • RunTests - Will run tests for dotnet, fable-javascript and fable-python projects
  • FormatCode - Will run fantomas to format the codebase

This is not an exhaustive list. Additional targets can be found in the ./build/build.fs file.

A motivating example

This example of composing a login flow shows one example of how this library can aid in clear, simple, and powerful error handling, using just a computation expression and a few helper functions. (The library has many more helper functions and computation expressions as well as infix operators; see the documentation for details.)

// Given the following functions:
//   tryGetUser: string -> Async<User option>
//   isPwdValid: string -> User -> bool
//   authorize: User -> Async<Result<unit, AuthError>>
//   createAuthToken: User -> Result<AuthToken, TokenError>

type LoginError = InvalidUser | InvalidPwd | Unauthorized of AuthError | TokenErr of TokenError

let login (username: string) (password: string) : Async<Result<AuthToken, LoginError>> =
  asyncResult {
    // requireSome unwraps a Some value or gives the specified error if None
    let! user = username |> tryGetUser |> AsyncResult.requireSome InvalidUser

    // requireTrue gives the specified error if false
    do! user |> isPwdValid password |> Result.requireTrue InvalidPwd

    // Error value is wrapped/transformed (Unauthorized has signature AuthError -> LoginError)
    do! user |> authorize |> AsyncResult.mapError Unauthorized

    // Same as above, but synchronous, so we use the built-in mapError
    return! user |> createAuthToken |> Result.mapError TokenErr
  }

Sponsor(s)

<a href="https://www.ajira.tech"><img src="./Ajira-logo.png" alt="Ajira Technologies, India" width="200" /></a>

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.  net9.0 is compatible.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 is compatible. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  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.

NuGet packages (37)

Showing the top 5 NuGet packages that depend on FsToolkit.ErrorHandling:

Package Downloads
FsToolkit.ErrorHandling.TaskResult

FsToolkit.ErrorHandling is an extensive utility library based around the F# Result type, enabling consistent and powerful error handling.
Oryx

.NET SDK for writing HTTP clients
FsToolkit.ErrorHandling.AsyncSeq

FsToolkit.ErrorHandling is an extensive utility library based around the F# Result type, enabling consistent and powerful error handling.
FsToolkit.ErrorHandling.IcedTasks

FsToolkit.ErrorHandling is an extensive utility library based around the F# Result type, enabling consistent and powerful error handling.
FsToolkit.ErrorHandling.JobResult

FsToolkit.ErrorHandling is an extensive utility library based around the F# Result type, enabling consistent and powerful error handling.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
5.0.0-beta011 37 3/30/2025
5.0.0-beta010 157 3/21/2025
5.0.0-beta009 451 3/5/2025
5.0.0-beta008 198 3/2/2025
5.0.0-beta007 462 2/23/2025
5.0.0-beta006 151 2/21/2025
5.0.0-beta005 155 2/16/2025
5.0.0-beta004 229 2/4/2025
5.0.0-beta003 348 1/6/2025
5.0.0-beta002 189 12/21/2024
5.0.0-beta001 1,874 12/7/2024
4.18.0 181,542 10/23/2024
4.18.0-beta001 170 10/23/2024
4.17.0 130,105 9/23/2024
4.17.0-beta002 168 9/23/2024
4.17.0-beta001 159 9/23/2024
4.16.0 72,232 7/15/2024
4.15.3 4,884 7/14/2024
4.15.3-beta001 242 7/14/2024
4.15.2 161,433 5/2/2024
4.15.2-beta001 243 5/2/2024
4.15.1 178,449 1/15/2024
4.15.0 57,811 1/10/2024
4.14.0 5,066 1/2/2024
4.13.0 14,558 12/10/2023
4.13.0-beta002 1,266 12/10/2023
4.13.0-beta001 1,226 12/10/2023
4.12.0 11,911 11/27/2023
4.11.1 4,877 11/23/2023
4.11.0 31,479 11/11/2023
4.10.0 22,490 10/16/2023
4.9.0 507,453 7/10/2023
4.8.0 3,332 7/7/2023
4.7.0 17,607 6/21/2023
4.7.0-beta001 1,737 6/21/2023
4.6.0 103,224 4/20/2023
4.6.0-beta001 1,828 4/20/2023
4.5.0 33,570 3/27/2023
4.5.0-beta002 1,805 3/19/2023
4.5.0-beta001 3,260 3/6/2023
4.4.0 182,331 2/21/2023
4.3.0 54,625 1/20/2023
4.2.1 22,784 12/19/2022
4.2.0 2,660 12/17/2022
4.1.0 10,647 12/13/2022
4.1.0-beta001 1,755 12/13/2022
4.0.0 65,050 11/19/2022
4.0.0-beta001 1,723 11/19/2022
3.3.1 70,292 11/19/2022
3.3.1-beta004 1,830 11/19/2022
3.3.1-beta003 1,723 11/18/2022
3.3.1-beta002 1,792 11/18/2022
3.3.1-beta001 1,710 11/18/2022
3.3.0-beta001 1,730 11/9/2022
3.2.0 132,178 10/31/2022
3.2.0-beta001 1,616 10/31/2022
3.1.0 26,469 10/19/2022
3.0.1 3,658 10/18/2022
3.0.0 8,637 10/14/2022
3.0.0-beta008 1,798 10/14/2022
3.0.0-beta007 33,808 4/15/2022
3.0.0-beta006 1,848 4/5/2022
3.0.0-beta005 1,877 4/5/2022
3.0.0-beta004 1,890 4/5/2022
3.0.0-beta003 1,810 3/30/2022
3.0.0-beta002 2,503 2/21/2022
3.0.0-beta001 1,806 2/21/2022
2.13.0 1,448,389 1/11/2022
2.13.0-beta001 1,773 1/11/2022
2.12.0 4,151 1/6/2022
2.12.0-beta001 1,765 1/6/2022
2.11.1 39,039 12/1/2021
2.11.1-beta001 2,369 12/1/2021
2.11.0 9,483 11/24/2021
2.11.0-beta004 4,835 11/24/2021
2.11.0-beta002 4,741 11/24/2021
2.11.0-beta001 4,677 11/24/2021
2.10.0 37,467 11/13/2021
2.9.0 8,057 11/10/2021
2.9.0-beta001 1,867 11/10/2021
2.8.1 7,818 11/7/2021
2.8.0 2,368 11/7/2021
2.8.0-beta001 2,046 11/7/2021
2.7.1 10,727 10/19/2021
2.7.1-beta001 1,903 10/19/2021
2.7.0 189,120 8/2/2021
2.7.0-beta001 2,014 8/2/2021
2.6.0 49,175 7/7/2021
2.6.0-beta001 2,005 7/7/2021
2.5.0 62,911 5/26/2021
2.5.0-beta001 2,072 5/26/2021
2.4.0 10,162 5/23/2021
2.4.0-beta001 1,953 5/23/2021
2.3.0 21,296 5/14/2021
2.3.0-beta002 1,885 5/14/2021
2.2.0 15,293 4/21/2021
2.1.2 87,651 2/27/2021
2.1.1 3,177 2/26/2021
2.1.1-beta001 2,021 2/26/2021
2.1.0 2,539 2/26/2021
2.1.0-beta003 2,095 2/26/2021
2.1.0-beta002 1,891 2/25/2021
2.1.0-beta001 2,046 2/25/2021
2.0.0 642,617 11/20/2020
2.0.0-beta002 2,274 11/18/2020
2.0.0-beta001 2,680 8/29/2020
1.4.3 258,452 7/22/2020
1.4.0 10,045 6/5/2020
1.3.2 2,764 6/5/2020
1.3.1 4,807 5/29/2020
1.3.1-beta001 2,288 5/25/2020
1.3.0 6,127 5/25/2020
1.3.0-beta006 2,224 5/25/2020
1.3.0-beta005 2,332 5/25/2020
1.3.0-beta004 2,314 5/12/2020
1.2.6 38,442 2/15/2020
1.2.5 30,766 10/18/2019
1.2.4 3,238 10/10/2019
1.2.3 117,879 7/22/2019
1.2.2 6,984 5/31/2019
1.2.1 28,464 5/22/2019
1.1.1 3,130 5/9/2019
1.1.0 2,879 5/7/2019
1.0.0 5,351 4/10/2019
0.0.14 2,846 1/27/2019
0.0.13 1,492 1/21/2019
0.0.12 1,841 1/4/2019
0.0.11 1,557 1/3/2019
0.0.10 1,530 12/30/2018
0.0.9 1,730 10/5/2018
0.0.8 1,631 10/5/2018
0.0.7 1,647 10/5/2018
0.0.6 1,583 10/4/2018
0.0.5 1,559 9/16/2018
0.0.4 1,583 9/16/2018
0.0.3 1,614 9/8/2018
0.0.2 1,613 9/8/2018
0.0.1 1,984 9/8/2018

- BREAKING: [Remove Ply and update to FSharp 6](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/248) Credits @TheAngryByrd
- BREAKING: [Remove MergeSources (and!) from some implementations like Result](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/261)  Credits @TheAngryByrd
- BREAKING: [Merge TaskResult into Core library](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/285) Credits @TheAngryByrd
- This means FsToolkit.ErrorHandling.TaskResult is no longer a separate package and will not be updated. It is now part of the core library.
- BREAKING: [Rename retn to singleton](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/287) Credits @1eyewonder
- BREAKING: [Rename returnError to error + documentation](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/311) Credits @tw0po1nt
- [Use Microsoft.Bcl.AsyncInterfaces in netstandard2.0 (Allows IAsyncDisposable and IAsyncEnumerable)](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/250) Credits @TheAngryByrd
- [Build against Net8](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/251) Credits @TheAngryByrd
- [Fix Overload Resolution to Align to Computation Expression used](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/252) Credits @TheAngryByrd
- [refactor!: Seq.sequenceResultM returns Array instead of seq](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/255) Credits @bartelink
- [feat(Seq): sequenceResultA](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/255) Credits @bartelink
- [Updated uses of Seq.append](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/290) Credits @1eyewonder
- [Add Option.traverseAsync and Option.sequenceAsync](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/298#event-15827853276) Credits @tw0po1nt
- [Add Require and Check helper methods](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/295) Credits @PI-Gorbo
- [Add new AsyncOption APIs and document all its other functions; minor fixes to documentation for Option module](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/307) Credits @tw0po1nt
- [F# 9 support and nullness](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/308) Credits @TheAngryByrd
- [Update IcedTasks 0.11.7](https://github.com/demystifyfp/FsToolkit.ErrorHandling/commit/0a4cc7b3c52efcef47dbc653b00d56ab029bbd01) Credits @TheAngryByrd
- [Add TaskValidation module](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/313) Credits @tw0po1nt
- [feat(Seq.traverse/sequence*)!: Yield arrays](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/310) Credits @bartelink
- [Add ParallelAsync CEs](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/318) Credits @njlr
- [Add Option.sequenceAsyncResult and Option.traverseAsyncResult](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/321) Credits @JayWearsSocks