FsToolkit.ErrorHandling 2.9.0-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There is a newer version of this package available.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 2.9.0-beta001
                    
NuGet\Install-Package FsToolkit.ErrorHandling -Version 2.9.0-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="2.9.0-beta001" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="FsToolkit.ErrorHandling" Version="2.9.0-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 2.9.0-beta001
                    
#r "nuget: FsToolkit.ErrorHandling, 2.9.0-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.
#addin nuget:?package=FsToolkit.ErrorHandling&version=2.9.0-beta001&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=FsToolkit.ErrorHandling&version=2.9.0-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

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 (40)

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
5.0.0 7,536 6/2/2025
5.0.0-beta014 204 6/2/2025
5.0.0-beta013 387 5/29/2025
5.0.0-beta012 1,487 5/1/2025
5.0.0-beta011 446 3/30/2025
5.0.0-beta010 236 3/21/2025
5.0.0-beta009 1,706 3/5/2025
5.0.0-beta008 410 3/2/2025
5.0.0-beta007 1,325 2/23/2025
5.0.0-beta006 176 2/21/2025
5.0.0-beta005 181 2/16/2025
5.0.0-beta004 366 2/4/2025
5.0.0-beta003 394 1/6/2025
5.0.0-beta002 215 12/21/2024
5.0.0-beta001 3,436 12/7/2024
4.18.0 413,429 10/23/2024
4.18.0-beta001 195 10/23/2024
4.17.0 183,346 9/23/2024
4.17.0-beta002 195 9/23/2024
4.17.0-beta001 185 9/23/2024
4.16.0 87,900 7/15/2024
4.15.3 5,024 7/14/2024
4.15.3-beta001 257 7/14/2024
4.15.2 191,828 5/2/2024
4.15.2-beta001 266 5/2/2024
4.15.1 190,844 1/15/2024
4.15.0 58,284 1/10/2024
4.14.0 5,142 1/2/2024
4.13.0 15,303 12/10/2023
4.13.0-beta002 1,283 12/10/2023
4.13.0-beta001 1,252 12/10/2023
4.12.0 12,601 11/27/2023
4.11.1 5,042 11/23/2023
4.11.0 32,723 11/11/2023
4.10.0 23,804 10/16/2023
4.9.0 541,462 7/10/2023
4.8.0 3,366 7/7/2023
4.7.0 18,387 6/21/2023
4.7.0-beta001 1,770 6/21/2023
4.6.0 116,713 4/20/2023
4.6.0-beta001 1,862 4/20/2023
4.5.0 33,717 3/27/2023
4.5.0-beta002 1,843 3/19/2023
4.5.0-beta001 3,292 3/6/2023
4.4.0 190,653 2/21/2023
4.3.0 55,039 1/20/2023
4.2.1 23,226 12/19/2022
4.2.0 2,692 12/17/2022
4.1.0 10,694 12/13/2022
4.1.0-beta001 1,786 12/13/2022
4.0.0 79,349 11/19/2022
4.0.0-beta001 1,758 11/19/2022
3.3.1 70,329 11/19/2022
3.3.1-beta004 1,862 11/19/2022
3.3.1-beta003 1,752 11/18/2022
3.3.1-beta002 1,820 11/18/2022
3.3.1-beta001 1,736 11/18/2022
3.3.0-beta001 1,780 11/9/2022
3.2.0 134,595 10/31/2022
3.2.0-beta001 1,644 10/31/2022
3.1.0 27,243 10/19/2022
3.0.1 3,686 10/18/2022
3.0.0 8,810 10/14/2022
3.0.0-beta008 1,830 10/14/2022
3.0.0-beta007 33,904 4/15/2022
3.0.0-beta006 1,886 4/5/2022
3.0.0-beta005 1,932 4/5/2022
3.0.0-beta004 1,928 4/5/2022
3.0.0-beta003 1,864 3/30/2022
3.0.0-beta002 2,541 2/21/2022
3.0.0-beta001 1,845 2/21/2022
2.13.0 1,569,496 1/11/2022
2.13.0-beta001 1,817 1/11/2022
2.12.0 4,198 1/6/2022
2.12.0-beta001 1,804 1/6/2022
2.11.1 39,817 12/1/2021
2.11.1-beta001 2,408 12/1/2021
2.11.0 9,530 11/24/2021
2.11.0-beta004 4,887 11/24/2021
2.11.0-beta002 4,787 11/24/2021
2.11.0-beta001 4,724 11/24/2021
2.10.0 37,539 11/13/2021
2.9.0 8,105 11/10/2021
2.9.0-beta001 1,907 11/10/2021
2.8.1 8,646 11/7/2021
2.8.0 2,407 11/7/2021
2.8.0-beta001 2,089 11/7/2021
2.7.1 10,834 10/19/2021
2.7.1-beta001 1,948 10/19/2021
2.7.0 206,072 8/2/2021
2.7.0-beta001 2,060 8/2/2021
2.6.0 49,585 7/7/2021
2.6.0-beta001 2,054 7/7/2021
2.5.0 63,443 5/26/2021
2.5.0-beta001 2,120 5/26/2021
2.4.0 10,208 5/23/2021
2.4.0-beta001 1,996 5/23/2021
2.3.0 21,339 5/14/2021
2.3.0-beta002 1,925 5/14/2021
2.2.0 15,361 4/21/2021
2.1.2 88,221 2/27/2021
2.1.1 3,226 2/26/2021
2.1.1-beta001 2,073 2/26/2021
2.1.0 2,597 2/26/2021
2.1.0-beta003 2,145 2/26/2021
2.1.0-beta002 1,947 2/25/2021
2.1.0-beta001 2,095 2/25/2021
2.0.0 668,012 11/20/2020
2.0.0-beta002 2,326 11/18/2020
2.0.0-beta001 2,733 8/29/2020
1.4.3 266,135 7/22/2020
1.4.0 10,334 6/5/2020
1.3.2 2,819 6/5/2020
1.3.1 4,869 5/29/2020
1.3.1-beta001 2,345 5/25/2020
1.3.0 6,453 5/25/2020
1.3.0-beta006 2,275 5/25/2020
1.3.0-beta005 2,385 5/25/2020
1.3.0-beta004 2,371 5/12/2020
1.2.6 39,031 2/15/2020
1.2.5 31,000 10/18/2019
1.2.4 3,296 10/10/2019
1.2.3 121,085 7/22/2019
1.2.2 7,038 5/31/2019
1.2.1 28,547 5/22/2019
1.1.1 3,198 5/9/2019
1.1.0 2,999 5/7/2019
1.0.0 5,428 4/10/2019
0.0.14 2,914 1/27/2019
0.0.13 1,556 1/21/2019
0.0.12 1,897 1/4/2019
0.0.11 1,637 1/3/2019
0.0.10 1,617 12/30/2018
0.0.9 1,820 10/5/2018
0.0.8 1,722 10/5/2018
0.0.7 1,730 10/5/2018
0.0.6 1,670 10/4/2018
0.0.5 1,647 9/16/2018
0.0.4 1,673 9/16/2018
0.0.3 1,704 9/8/2018
0.0.2 1,702 9/8/2018
0.0.1 2,162 9/8/2018