FsToolkit.ErrorHandling.IcedTasks 5.0.0-beta001

This is a prerelease version of FsToolkit.ErrorHandling.IcedTasks.

There is a newer version of this package available.
See the version list below for details.

dotnet add package FsToolkit.ErrorHandling.IcedTasks --version 5.0.0-beta001

NuGet\Install-Package FsToolkit.ErrorHandling.IcedTasks -Version 5.0.0-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.IcedTasks" Version="5.0.0-beta001" />

For projects that support PackageReference, copy this XML node into the project file to reference the package.

<PackageVersion Include="FsToolkit.ErrorHandling.IcedTasks" Version="5.0.0-beta001" />
                    

                            Directory.Packages.props

<PackageReference Include="FsToolkit.ErrorHandling.IcedTasks" />
                    

                            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.IcedTasks --version 5.0.0-beta001

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

#r "nuget: FsToolkit.ErrorHandling.IcedTasks, 5.0.0-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.IcedTasks@5.0.0-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.IcedTasks&version=5.0.0-beta001&prerelease
                    

                            Install as a Cake Addin

#tool nuget:?package=FsToolkit.ErrorHandling.IcedTasks&version=5.0.0-beta001&prerelease
                    

                            Install as a Cake Tool

The NuGet Team does not provide support for this client. Please contact its maintainers for support.

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, .NET Standard2.1 and supports Fable.

Documentation

The documentation is available here.

Further material

The main resource as to learning this style of programming Railway Oriented Programming
However Result isn't a panacea, see what pitfalls and where you shouldn't use Result. In defense of Exceptions: Throw (away) your Result

Builds

GitHub Actions

NuGet

Package name	Release	Prelease
FsToolkit.ErrorHandling
FsToolkit.ErrorHandling.TaskResult
FsToolkit.ErrorHandling.JobResult
FsToolkit.ErrorHandling.AsyncSeq
FsToolkit.ErrorHandling.IcedTasks

Developing locally

Devcontainer

This repository has a devcontainer setup for VSCode. For more infomation see:

VSCode

Local Setup

.NET Core SDK
- v6.x
- v7.x
- v8.x

Optional

To test fable builds locally you will need:

Node
- v18.0.0 or Higher
- Not required but recommend that you use NVM to easily manage multiple versions of Node
Python
- v3.10.0 or higher
- Required for Fable-Python

Compiling

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

Without specifying a build target, the default target is DotnetPack, which will run tests for all projects on dotnet and then pack the projects into nuget packages. For additional notable targets see below.

Build Targets

Clean - Will clean all projects bin and obj folders
DotnetTest - Will run tests for dotnet projects
NpmTest - Will run tests for fable-javascript projects
PythonTest - Will run tests for fable-python projects
RunTests - Will run tests for dotnet, fable-javascript and fable-python projects
FormatCode - Will run fantomas to format the codebase

This is not an exhausting list. Additional targets can be found in the ./build/build.fs file.

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)

Product	Compatible and additional computed target framework versions.
.NET	net5.0 was computed. net5.0-windows was computed. net6.0 is compatible. 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.

.NETStandard 2.0
- FSharp.Core (>= 6.0.1)
- FsToolkit.ErrorHandling (>= 5.0.0-beta001)
- IcedTasks (>= 0.11.4)
- Microsoft.Bcl.AsyncInterfaces (>= 6.0.0)
.NETStandard 2.1
- FSharp.Core (>= 6.0.1)
- FsToolkit.ErrorHandling (>= 5.0.0-beta001)
- IcedTasks (>= 0.11.4)
net6.0
- FSharp.Core (>= 6.0.1)
- FsToolkit.ErrorHandling (>= 5.0.0-beta001)
- IcedTasks (>= 0.11.4)

NuGet packages (1)

Showing the top 1 NuGet packages that depend on FsToolkit.ErrorHandling.IcedTasks:

Package	Downloads
NBomber Modern and flexible load testing framework for Pull and Push scenarios, designed to test any system regardless a protocol (HTTP/WebSockets/AMQP etc) or a semantic model (Pull/Push).	3.5M

GitHub repositories

This package is not used by any popular GitHub repositories.

Version	Downloads	Last Updated
5.0.1	1,624	7/12/2025
5.0.0	383	6/2/2025
5.0.0-beta014	162	6/2/2025
5.0.0-beta013	161	5/29/2025
5.0.0-beta012	1,631	5/1/2025
5.0.0-beta011	230	3/30/2025
5.0.0-beta010	138	3/21/2025
5.0.0-beta009	1,356	3/5/2025
5.0.0-beta008	141	3/2/2025
5.0.0-beta007	298	2/23/2025
5.0.0-beta006	122	2/21/2025
5.0.0-beta005	134	2/16/2025
5.0.0-beta004	135	2/4/2025
5.0.0-beta003	126	1/6/2025
5.0.0-beta002	122	12/21/2024
5.0.0-beta001	134	12/7/2024
4.18.0	299,218	10/23/2024
4.18.0-beta001	118	10/23/2024
4.17.0	260	9/23/2024
4.17.0-beta002	125	9/23/2024
4.17.0-beta001	114	9/23/2024
4.16.0	821	7/15/2024
4.15.3	154	7/14/2024
4.15.3-beta001	130	7/14/2024
4.15.2	650	5/2/2024
4.15.2-beta001	103	5/2/2024
4.15.1	226	1/15/2024
4.15.0	161	1/10/2024
4.14.0	195	1/2/2024
4.13.0	207	12/10/2023
4.13.0-beta002	158	12/10/2023
4.13.0-beta001	151	12/10/2023
4.12.0	207	11/27/2023
4.11.1	191	11/23/2023
4.11.0	173	11/11/2023
4.10.0	196	10/16/2023
4.9.0	268	7/10/2023
4.8.0	221	7/7/2023
4.7.0	206	6/21/2023
4.7.0-beta001	192	6/21/2023
4.6.0	247	4/20/2023
4.6.0-beta001	208	4/20/2023
4.5.0	293	3/27/2023
4.5.0-beta002	221	3/19/2023
4.5.0-beta001	209	3/6/2023
4.4.0	320	2/21/2023
4.3.0	385	1/20/2023
4.2.1	439	12/19/2022
4.2.0	422	12/17/2022
4.1.0	383	12/13/2022
4.1.0-beta001	223	12/13/2022
4.0.0	432	11/19/2022
4.0.0-beta001	242	11/19/2022
3.3.1	415	11/19/2022
3.3.1-beta004	227	11/19/2022
3.3.1-beta003	218	11/18/2022
3.3.1-beta002	232	11/18/2022
3.3.1-beta001	221	11/18/2022
3.3.0-beta001	247	11/9/2022
3.2.0	452	10/31/2022
3.2.0-beta001	232	10/31/2022
3.1.0	521	10/19/2022
3.0.1	465	10/18/2022
3.0.0	520	10/14/2022
3.0.0-beta008	240	10/14/2022
3.0.0-beta007	276	4/15/2022
3.0.0-beta006	264	4/5/2022
3.0.0-beta005	263	4/5/2022
3.0.0-beta004	264	4/5/2022

- BREAKING: [Remove Ply and update to FSharp 6](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/248) Credits @TheAngryByrd
- BREAKING: [Remove MergeSources (and!) from some implementations](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/261) Credits @TheAngryByrd
- BREAKING: [Merge TaskResult into Core library](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/285) Credits @TheAngryByrd
- This means FsToolkit.ErrorHandling.TaskResult is no longer a separate package and will not be updated. It is now part of the core library.
- [Use Microsoft.Bcl.AsyncInterfaces in netstandard2.0 (Allows IAsyncDisposable and IAsyncEnumerable)](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/250) Credits @TheAngryByrd
- [Build against Net8](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/251) Credits @TheAngryByrd
- [Fix Overload Resolution to Align to Computation Expression used](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/252) Credits @TheAngryByrd
- [refactor!: Seq.sequenceResultM returns Array instead of seq](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/255) Credits @bartelink
- [feat(Seq): sequenceResultA](https://github.com/demystifyfp/FsToolkit.ErrorHandling/pull/255) Credits @bartelink
-