FsToolkit.ErrorHandling 3.2.0-beta001

This is a prerelease version of FsToolkit.ErrorHandling.
There is a newer version of this package available.
See the version list below for details.
dotnet add package FsToolkit.ErrorHandling --version 3.2.0-beta001
                    
NuGet\Install-Package FsToolkit.ErrorHandling -Version 3.2.0-beta001
                    
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="3.2.0-beta001" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="FsToolkit.ErrorHandling" Version="3.2.0-beta001" />
                    
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 3.2.0-beta001
                    
#r "nuget: FsToolkit.ErrorHandling, 3.2.0-beta001"
                    
#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.
#:package FsToolkit.ErrorHandling@3.2.0-beta001
                    
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.
#addin nuget:?package=FsToolkit.ErrorHandling&version=3.2.0-beta001&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=FsToolkit.ErrorHandling&version=3.2.0-beta001&prerelease
                    
Install 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 and .NET Framework 4.6.1 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

Requirements
Compiling
> build.cmd <optional buildtarget> // on windows
$ ./build.sh  <optional buildtarget>// on unix

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 was computed.  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.  net10.0 was computed.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-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 (43)

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.IcedTasks

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

FsToolkit.ErrorHandling.AsyncSeq

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
5.1.0 4,372 9/26/2025
5.1.0-beta001 235 9/26/2025
5.0.1 30,117 7/12/2025
5.0.0 16,009 6/2/2025
5.0.0-beta014 322 6/2/2025
5.0.0-beta013 500 5/29/2025
5.0.0-beta012 2,139 5/1/2025
5.0.0-beta011 640 3/30/2025
5.0.0-beta010 344 3/21/2025
5.0.0-beta009 1,874 3/5/2025
5.0.0-beta008 525 3/2/2025
5.0.0-beta007 1,694 2/23/2025
5.0.0-beta006 282 2/21/2025
5.0.0-beta005 278 2/16/2025
5.0.0-beta004 472 2/4/2025
5.0.0-beta003 539 1/6/2025
5.0.0-beta002 318 12/21/2024
5.0.0-beta001 4,760 12/7/2024
4.18.0 652,609 10/23/2024
4.18.0-beta001 308 10/23/2024
4.17.0 209,327 9/23/2024
4.17.0-beta002 317 9/23/2024
4.17.0-beta001 324 9/23/2024
4.16.0 105,706 7/15/2024
4.15.3 5,303 7/14/2024
4.15.3-beta001 356 7/14/2024
4.15.2 206,809 5/2/2024
4.15.2-beta001 392 5/2/2024
4.15.1 202,544 1/15/2024
4.15.0 58,433 1/10/2024
4.14.0 5,378 1/2/2024
4.13.0 15,756 12/10/2023
4.13.0-beta002 1,400 12/10/2023
4.13.0-beta001 1,368 12/10/2023
4.12.0 13,131 11/27/2023
4.11.1 5,183 11/23/2023
4.11.0 34,009 11/11/2023
4.10.0 25,386 10/16/2023
4.9.0 574,467 7/10/2023
4.8.0 3,590 7/7/2023
4.7.0 19,314 6/21/2023
4.7.0-beta001 1,909 6/21/2023
4.6.0 128,706 4/20/2023
4.6.0-beta001 2,004 4/20/2023
4.5.0 35,103 3/27/2023
4.5.0-beta002 1,996 3/19/2023
4.5.0-beta001 3,441 3/6/2023
4.4.0 195,391 2/21/2023
4.3.0 55,577 1/20/2023
4.2.1 23,587 12/19/2022
4.2.0 2,834 12/17/2022
4.1.0 10,845 12/13/2022
4.1.0-beta001 1,925 12/13/2022
4.0.0 90,287 11/19/2022
4.0.0-beta001 1,902 11/19/2022
3.3.1 70,717 11/19/2022
3.3.1-beta004 1,995 11/19/2022
3.3.1-beta003 1,877 11/18/2022
3.3.1-beta002 1,969 11/18/2022
3.3.1-beta001 1,868 11/18/2022
3.3.0-beta001 1,910 11/9/2022
3.2.0 137,351 10/31/2022
3.2.0-beta001 1,779 10/31/2022
3.1.0 27,642 10/19/2022
3.0.1 3,842 10/18/2022
3.0.0 9,060 10/14/2022
3.0.0-beta008 1,979 10/14/2022
3.0.0-beta007 34,058 4/15/2022
3.0.0-beta006 2,033 4/5/2022
3.0.0-beta005 2,098 4/5/2022
3.0.0-beta004 2,062 4/5/2022
3.0.0-beta003 1,995 3/30/2022
3.0.0-beta002 2,669 2/21/2022
3.0.0-beta001 1,974 2/21/2022
2.13.0 1,678,222 1/11/2022
2.13.0-beta001 1,953 1/11/2022
2.12.0 4,345 1/6/2022
2.12.0-beta001 1,944 1/6/2022
2.11.1 40,276 12/1/2021
2.11.1-beta001 2,537 12/1/2021
2.11.0 9,658 11/24/2021
2.11.0-beta004 5,030 11/24/2021
2.11.0-beta002 4,934 11/24/2021
2.11.0-beta001 4,854 11/24/2021
2.10.0 37,703 11/13/2021
2.9.0 8,226 11/10/2021
2.9.0-beta001 2,011 11/10/2021
2.8.1 9,091 11/7/2021
2.8.0 2,509 11/7/2021
2.8.0-beta001 2,188 11/7/2021
2.7.1 10,964 10/19/2021
2.7.1-beta001 2,064 10/19/2021
2.7.0 222,745 8/2/2021
2.7.0-beta001 2,191 8/2/2021
2.6.0 49,971 7/7/2021
2.6.0-beta001 2,169 7/7/2021
2.5.0 64,133 5/26/2021
2.5.0-beta001 2,253 5/26/2021
2.4.0 10,327 5/23/2021
2.4.0-beta001 2,108 5/23/2021
2.3.0 21,440 5/14/2021
2.3.0-beta002 2,039 5/14/2021
2.2.0 15,485 4/21/2021
2.1.2 91,355 2/27/2021
2.1.1 3,458 2/26/2021
2.1.1-beta001 2,182 2/26/2021
2.1.0 2,721 2/26/2021
2.1.0-beta003 2,266 2/26/2021
2.1.0-beta002 2,067 2/25/2021
2.1.0-beta001 2,223 2/25/2021
2.0.0 687,722 11/20/2020
2.0.0-beta002 2,442 11/18/2020
2.0.0-beta001 2,847 8/29/2020
1.4.3 272,081 7/22/2020
1.4.0 10,653 6/5/2020
1.3.2 2,982 6/5/2020
1.3.1 5,012 5/29/2020
1.3.1-beta001 2,466 5/25/2020
1.3.0 6,647 5/25/2020
1.3.0-beta006 2,417 5/25/2020
1.3.0-beta005 2,504 5/25/2020
1.3.0-beta004 2,545 5/12/2020
1.2.6 39,608 2/15/2020
1.2.5 31,202 10/18/2019
1.2.4 3,432 10/10/2019
1.2.3 124,464 7/22/2019
1.2.2 7,176 5/31/2019
1.2.1 29,081 5/22/2019
1.1.1 3,394 5/9/2019
1.1.0 3,133 5/7/2019
1.0.0 5,603 4/10/2019
0.0.14 3,000 1/27/2019
0.0.13 1,648 1/21/2019
0.0.12 1,975 1/4/2019
0.0.11 1,720 1/3/2019
0.0.10 1,699 12/30/2018
0.0.9 1,909 10/5/2018
0.0.8 1,816 10/5/2018
0.0.7 1,818 10/5/2018
0.0.6 1,761 10/4/2018
0.0.5 1,733 9/16/2018
0.0.4 1,755 9/16/2018
0.0.3 1,792 9/8/2018
0.0.2 1,788 9/8/2018
0.0.1 2,583 9/8/2018