FsToolkit.ErrorHandling.AsyncSeq 3.0.0-beta008

This is a prerelease version of FsToolkit.ErrorHandling.AsyncSeq.
There is a newer version of this package available.
See the version list below for details.
dotnet add package FsToolkit.ErrorHandling.AsyncSeq --version 3.0.0-beta008
                    
NuGet\Install-Package FsToolkit.ErrorHandling.AsyncSeq -Version 3.0.0-beta008
                    
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.AsyncSeq" Version="3.0.0-beta008" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="FsToolkit.ErrorHandling.AsyncSeq" Version="3.0.0-beta008" />
                    
Directory.Packages.props
<PackageReference Include="FsToolkit.ErrorHandling.AsyncSeq" />
                    
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.AsyncSeq --version 3.0.0-beta008
                    
#r "nuget: FsToolkit.ErrorHandling.AsyncSeq, 3.0.0-beta008"
                    
#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.AsyncSeq&version=3.0.0-beta008&prerelease
                    
Install as a Cake Addin
#tool nuget:?package=FsToolkit.ErrorHandling.AsyncSeq&version=3.0.0-beta008&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

This package is not used by any NuGet packages.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
5.0.0 150 6/2/2025
5.0.0-beta014 125 6/2/2025
5.0.0-beta013 133 5/29/2025
5.0.0-beta012 470 5/1/2025
5.0.0-beta011 174 3/30/2025
5.0.0-beta010 111 3/21/2025
5.0.0-beta009 710 3/5/2025
5.0.0-beta008 109 3/2/2025
5.0.0-beta007 156 2/23/2025
5.0.0-beta006 102 2/21/2025
5.0.0-beta005 103 2/16/2025
5.0.0-beta004 112 2/4/2025
5.0.0-beta003 103 1/6/2025
5.0.0-beta002 102 12/21/2024
5.0.0-beta001 106 12/7/2024
4.18.0 29,149 10/23/2024
4.18.0-beta001 88 10/23/2024
4.17.0 210 9/23/2024
4.17.0-beta002 79 9/23/2024
4.17.0-beta001 91 9/23/2024
4.16.0 412 7/15/2024
4.15.3 147 7/14/2024
4.15.3-beta001 98 7/14/2024
4.15.2 213 5/2/2024
4.15.2-beta001 93 5/2/2024
4.15.1 555 1/15/2024
4.15.0 42,012 1/10/2024
4.14.0 436 1/2/2024
4.13.0 213 12/10/2023
4.13.0-beta002 123 12/10/2023
4.13.0-beta001 107 12/10/2023
4.12.0 176 11/27/2023
4.11.1 168 11/23/2023
4.11.0 160 11/11/2023
4.10.0 203 10/16/2023
4.9.0 2,064 7/10/2023
4.8.0 203 7/7/2023
4.7.0 206 6/21/2023
4.7.0-beta001 154 6/21/2023
4.6.0 2,728 4/20/2023
4.6.0-beta001 137 4/20/2023
4.5.0 1,139 3/27/2023
4.5.0-beta002 141 3/19/2023
4.5.0-beta001 159 3/6/2023
4.4.0 286 2/21/2023
4.3.0 361 1/20/2023
4.2.1 343 12/19/2022
4.2.0 347 12/17/2022
4.1.0 308 12/13/2022
4.1.0-beta001 151 12/13/2022
4.0.0 421 11/19/2022
4.0.0-beta001 179 11/19/2022
3.3.1 41,326 11/19/2022
3.3.1-beta004 166 11/19/2022
3.3.1-beta003 175 11/18/2022
3.3.1-beta002 141 11/18/2022
3.3.1-beta001 171 11/18/2022
3.3.0-beta001 169 11/9/2022
3.2.0 4,565 10/31/2022
3.2.0-beta001 154 10/31/2022
3.1.0 552 10/19/2022
3.0.1 418 10/18/2022
3.0.0 488 10/14/2022
3.0.0-beta008 188 10/14/2022
3.0.0-beta007 9,193 4/15/2022
3.0.0-beta006 200 4/5/2022
3.0.0-beta005 215 4/5/2022
3.0.0-beta004 182 4/5/2022
3.0.0-beta003 196 3/30/2022
3.0.0-beta002 197 2/21/2022
3.0.0-beta001 218 2/21/2022
2.13.0 6,703 1/11/2022
2.13.0-beta001 240 1/11/2022
2.12.0 326 1/6/2022
2.12.0-beta001 220 1/6/2022
2.11.1 1,466 12/1/2021
2.11.1-beta001 816 12/1/2021
2.11.0 3,290 11/24/2021
2.11.0-beta004 3,224 11/24/2021
2.11.0-beta002 3,237 11/24/2021
2.11.0-beta001 3,148 11/24/2021

- [Fixing stackoverflows in large while loops](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/182) Credits [@TheAngryByrd](https://github.com/TheAngryByrd)