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There is a newer version of this package available.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
5.1.0 561 9/26/2025
5.1.0-beta001 168 9/26/2025
5.0.1 25,589 7/12/2025
5.0.0 14,796 6/2/2025
5.0.0-beta014 292 6/2/2025
5.0.0-beta013 470 5/29/2025
5.0.0-beta012 2,099 5/1/2025
5.0.0-beta011 603 3/30/2025
5.0.0-beta010 311 3/21/2025
5.0.0-beta009 1,841 3/5/2025
5.0.0-beta008 489 3/2/2025
5.0.0-beta007 1,632 2/23/2025
5.0.0-beta006 249 2/21/2025
5.0.0-beta005 250 2/16/2025
5.0.0-beta004 438 2/4/2025
5.0.0-beta003 494 1/6/2025
5.0.0-beta002 283 12/21/2024
5.0.0-beta001 4,408 12/7/2024
4.18.0 613,021 10/23/2024
4.18.0-beta001 276 10/23/2024
4.17.0 205,442 9/23/2024
4.17.0-beta002 275 9/23/2024
4.17.0-beta001 278 9/23/2024
4.16.0 103,150 7/15/2024
4.15.3 5,236 7/14/2024
4.15.3-beta001 335 7/14/2024
4.15.2 205,175 5/2/2024
4.15.2-beta001 358 5/2/2024
4.15.1 200,435 1/15/2024
4.15.0 58,396 1/10/2024
4.14.0 5,294 1/2/2024
4.13.0 15,661 12/10/2023
4.13.0-beta002 1,371 12/10/2023
4.13.0-beta001 1,331 12/10/2023
4.12.0 13,006 11/27/2023
4.11.1 5,151 11/23/2023
4.11.0 33,912 11/11/2023
4.10.0 25,237 10/16/2023
4.9.0 568,986 7/10/2023
4.8.0 3,512 7/7/2023
4.7.0 19,184 6/21/2023
4.7.0-beta001 1,880 6/21/2023
4.6.0 126,295 4/20/2023
4.6.0-beta001 1,970 4/20/2023
4.5.0 34,607 3/27/2023
4.5.0-beta002 1,951 3/19/2023
4.5.0-beta001 3,404 3/6/2023
4.4.0 194,418 2/21/2023
4.3.0 55,426 1/20/2023
4.2.1 23,520 12/19/2022
4.2.0 2,796 12/17/2022
4.1.0 10,809 12/13/2022
4.1.0-beta001 1,890 12/13/2022
4.0.0 88,285 11/19/2022
4.0.0-beta001 1,860 11/19/2022
3.3.1 70,575 11/19/2022
3.3.1-beta004 1,960 11/19/2022
3.3.1-beta003 1,847 11/18/2022
3.3.1-beta002 1,938 11/18/2022
3.3.1-beta001 1,838 11/18/2022
3.3.0-beta001 1,878 11/9/2022
3.2.0 136,792 10/31/2022
3.2.0-beta001 1,753 10/31/2022
3.1.0 27,589 10/19/2022
3.0.1 3,797 10/18/2022
3.0.0 9,019 10/14/2022
3.0.0-beta008 1,943 10/14/2022
3.0.0-beta007 34,016 4/15/2022
3.0.0-beta006 1,995 4/5/2022
3.0.0-beta005 2,047 4/5/2022
3.0.0-beta004 2,039 4/5/2022
3.0.0-beta003 1,969 3/30/2022
3.0.0-beta002 2,641 2/21/2022
3.0.0-beta001 1,949 2/21/2022
2.13.0 1,659,918 1/11/2022
2.13.0-beta001 1,915 1/11/2022
2.12.0 4,312 1/6/2022
2.12.0-beta001 1,915 1/6/2022
2.11.1 40,163 12/1/2021
2.11.1-beta001 2,511 12/1/2021
2.11.0 9,629 11/24/2021
2.11.0-beta004 5,009 11/24/2021
2.11.0-beta002 4,914 11/24/2021
2.11.0-beta001 4,816 11/24/2021
2.10.0 37,663 11/13/2021
2.9.0 8,205 11/10/2021
2.9.0-beta001 1,987 11/10/2021
2.8.1 9,025 11/7/2021
2.8.0 2,483 11/7/2021
2.8.0-beta001 2,161 11/7/2021
2.7.1 10,947 10/19/2021
2.7.1-beta001 2,049 10/19/2021
2.7.0 220,559 8/2/2021
2.7.0-beta001 2,161 8/2/2021
2.6.0 49,939 7/7/2021
2.6.0-beta001 2,152 7/7/2021
2.5.0 63,982 5/26/2021
2.5.0-beta001 2,223 5/26/2021
2.4.0 10,299 5/23/2021
2.4.0-beta001 2,093 5/23/2021
2.3.0 21,423 5/14/2021
2.3.0-beta002 2,029 5/14/2021
2.2.0 15,462 4/21/2021
2.1.2 90,334 2/27/2021
2.1.1 3,395 2/26/2021
2.1.1-beta001 2,173 2/26/2021
2.1.0 2,700 2/26/2021
2.1.0-beta003 2,242 2/26/2021
2.1.0-beta002 2,038 2/25/2021
2.1.0-beta001 2,195 2/25/2021
2.0.0 684,516 11/20/2020
2.0.0-beta002 2,416 11/18/2020
2.0.0-beta001 2,827 8/29/2020
1.4.3 270,546 7/22/2020
1.4.0 10,584 6/5/2020
1.3.2 2,916 6/5/2020
1.3.1 4,989 5/29/2020
1.3.1-beta001 2,446 5/25/2020
1.3.0 6,611 5/25/2020
1.3.0-beta006 2,364 5/25/2020
1.3.0-beta005 2,482 5/25/2020
1.3.0-beta004 2,497 5/12/2020
1.2.6 39,384 2/15/2020
1.2.5 31,151 10/18/2019
1.2.4 3,403 10/10/2019
1.2.3 123,375 7/22/2019
1.2.2 7,156 5/31/2019
1.2.1 28,833 5/22/2019
1.1.1 3,287 5/9/2019
1.1.0 3,119 5/7/2019
1.0.0 5,551 4/10/2019
0.0.14 2,986 1/27/2019
0.0.13 1,633 1/21/2019
0.0.12 1,962 1/4/2019
0.0.11 1,704 1/3/2019
0.0.10 1,686 12/30/2018
0.0.9 1,894 10/5/2018
0.0.8 1,804 10/5/2018
0.0.7 1,806 10/5/2018
0.0.6 1,753 10/4/2018
0.0.5 1,721 9/16/2018
0.0.4 1,745 9/16/2018
0.0.3 1,777 9/8/2018
0.0.2 1,775 9/8/2018
0.0.1 2,483 9/8/2018