FsToolkit.ErrorHandling 2.12.0-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There is a newer version of this package available.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 2.12.0-beta001
                    
NuGet\Install-Package FsToolkit.ErrorHandling -Version 2.12.0-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="2.12.0-beta001" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="FsToolkit.ErrorHandling" Version="2.12.0-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 2.12.0-beta001
                    
#r "nuget: FsToolkit.ErrorHandling, 2.12.0-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@2.12.0-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=2.12.0-beta001&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=FsToolkit.ErrorHandling&version=2.12.0-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 Badge
FsToolkit.ErrorHandling NuGet
FsToolkit.ErrorHandling.TaskResult NuGet
FsToolkit.ErrorHandling.JobResult NuGet
FsToolkit.ErrorHandling.AsyncSeq NuGet

Developing locally

Requirements
  • .NET Core SDK
    • v3.1.200 or higher
    • Install from here.
  • Node
    • v10.15.0 or LTS
    • Not required but recommend that you use NVM to easily manage multiple versions of Node
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 was computed. 
.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
5.0.1 18,533 7/12/2025
5.0.0 13,239 6/2/2025
5.0.0-beta014 235 6/2/2025
5.0.0-beta013 416 5/29/2025
5.0.0-beta012 1,986 5/1/2025
5.0.0-beta011 552 3/30/2025
5.0.0-beta010 263 3/21/2025
5.0.0-beta009 1,790 3/5/2025
5.0.0-beta008 437 3/2/2025
5.0.0-beta007 1,533 2/23/2025
5.0.0-beta006 192 2/21/2025
5.0.0-beta005 201 2/16/2025
5.0.0-beta004 390 2/4/2025
5.0.0-beta003 433 1/6/2025
5.0.0-beta002 238 12/21/2024
5.0.0-beta001 4,216 12/7/2024
4.18.0 568,102 10/23/2024
4.18.0-beta001 218 10/23/2024
4.17.0 201,047 9/23/2024
4.17.0-beta002 209 9/23/2024
4.17.0-beta001 207 9/23/2024
4.16.0 100,827 7/15/2024
4.15.3 5,094 7/14/2024
4.15.3-beta001 269 7/14/2024
4.15.2 202,375 5/2/2024
4.15.2-beta001 286 5/2/2024
4.15.1 198,038 1/15/2024
4.15.0 58,317 1/10/2024
4.14.0 5,180 1/2/2024
4.13.0 15,486 12/10/2023
4.13.0-beta002 1,297 12/10/2023
4.13.0-beta001 1,273 12/10/2023
4.12.0 12,834 11/27/2023
4.11.1 5,075 11/23/2023
4.11.0 33,638 11/11/2023
4.10.0 24,759 10/16/2023
4.9.0 562,948 7/10/2023
4.8.0 3,403 7/7/2023
4.7.0 19,031 6/21/2023
4.7.0-beta001 1,804 6/21/2023
4.6.0 121,430 4/20/2023
4.6.0-beta001 1,896 4/20/2023
4.5.0 33,822 3/27/2023
4.5.0-beta002 1,877 3/19/2023
4.5.0-beta001 3,328 3/6/2023
4.4.0 193,161 2/21/2023
4.3.0 55,323 1/20/2023
4.2.1 23,425 12/19/2022
4.2.0 2,729 12/17/2022
4.1.0 10,730 12/13/2022
4.1.0-beta001 1,821 12/13/2022
4.0.0 86,190 11/19/2022
4.0.0-beta001 1,790 11/19/2022
3.3.1 70,365 11/19/2022
3.3.1-beta004 1,891 11/19/2022
3.3.1-beta003 1,786 11/18/2022
3.3.1-beta002 1,857 11/18/2022
3.3.1-beta001 1,768 11/18/2022
3.3.0-beta001 1,818 11/9/2022
3.2.0 136,268 10/31/2022
3.2.0-beta001 1,682 10/31/2022
3.1.0 27,441 10/19/2022
3.0.1 3,726 10/18/2022
3.0.0 8,892 10/14/2022
3.0.0-beta008 1,869 10/14/2022
3.0.0-beta007 33,954 4/15/2022
3.0.0-beta006 1,927 4/5/2022
3.0.0-beta005 1,971 4/5/2022
3.0.0-beta004 1,968 4/5/2022
3.0.0-beta003 1,903 3/30/2022
3.0.0-beta002 2,580 2/21/2022
3.0.0-beta001 1,883 2/21/2022
2.13.0 1,638,724 1/11/2022
2.13.0-beta001 1,855 1/11/2022
2.12.0 4,245 1/6/2022
2.12.0-beta001 1,844 1/6/2022
2.11.1 40,025 12/1/2021
2.11.1-beta001 2,446 12/1/2021
2.11.0 9,563 11/24/2021
2.11.0-beta004 4,931 11/24/2021
2.11.0-beta002 4,831 11/24/2021
2.11.0-beta001 4,767 11/24/2021
2.10.0 37,584 11/13/2021
2.9.0 8,144 11/10/2021
2.9.0-beta001 1,943 11/10/2021
2.8.1 8,896 11/7/2021
2.8.0 2,437 11/7/2021
2.8.0-beta001 2,123 11/7/2021
2.7.1 10,894 10/19/2021
2.7.1-beta001 1,987 10/19/2021
2.7.0 217,751 8/2/2021
2.7.0-beta001 2,104 8/2/2021
2.6.0 49,852 7/7/2021
2.6.0-beta001 2,095 7/7/2021
2.5.0 63,836 5/26/2021
2.5.0-beta001 2,161 5/26/2021
2.4.0 10,243 5/23/2021
2.4.0-beta001 2,027 5/23/2021
2.3.0 21,369 5/14/2021
2.3.0-beta002 1,963 5/14/2021
2.2.0 15,404 4/21/2021
2.1.2 88,610 2/27/2021
2.1.1 3,272 2/26/2021
2.1.1-beta001 2,113 2/26/2021
2.1.0 2,638 2/26/2021
2.1.0-beta003 2,189 2/26/2021
2.1.0-beta002 1,990 2/25/2021
2.1.0-beta001 2,137 2/25/2021
2.0.0 680,022 11/20/2020
2.0.0-beta002 2,369 11/18/2020
2.0.0-beta001 2,772 8/29/2020
1.4.3 269,173 7/22/2020
1.4.0 10,486 6/5/2020
1.3.2 2,863 6/5/2020
1.3.1 4,909 5/29/2020
1.3.1-beta001 2,391 5/25/2020
1.3.0 6,561 5/25/2020
1.3.0-beta006 2,315 5/25/2020
1.3.0-beta005 2,424 5/25/2020
1.3.0-beta004 2,414 5/12/2020
1.2.6 39,136 2/15/2020
1.2.5 31,049 10/18/2019
1.2.4 3,333 10/10/2019
1.2.3 122,380 7/22/2019
1.2.2 7,086 5/31/2019
1.2.1 28,599 5/22/2019
1.1.1 3,249 5/9/2019
1.1.0 3,060 5/7/2019
1.0.0 5,482 4/10/2019
0.0.14 2,956 1/27/2019
0.0.13 1,603 1/21/2019
0.0.12 1,936 1/4/2019
0.0.11 1,676 1/3/2019
0.0.10 1,658 12/30/2018
0.0.9 1,864 10/5/2018
0.0.8 1,767 10/5/2018
0.0.7 1,779 10/5/2018
0.0.6 1,725 10/4/2018
0.0.5 1,695 9/16/2018
0.0.4 1,716 9/16/2018
0.0.3 1,748 9/8/2018
0.0.2 1,748 9/8/2018
0.0.1 2,422 9/8/2018

- [Option/ValueOption.tryGetValue and reduce testing complexity](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/163) Credits [@TheAngryByrd](https://github.com/TheAngryByrd)