Fable.Compiler 5.5.0

.NET 10.0 This package targets .NET 10.0. The package is compatible with this framework or higher. 
dotnet add package Fable.Compiler --version 5.5.0
                    


                    

                
NuGet\Install-Package Fable.Compiler -Version 5.5.0
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="Fable.Compiler" Version="5.5.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="Fable.Compiler" Version="5.5.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="Fable.Compiler" />
                    


                            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 Fable.Compiler --version 5.5.0
                    


                    

                
#r "nuget: Fable.Compiler, 5.5.0"
#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 Fable.Compiler@5.5.0
#: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=Fable.Compiler&version=5.5.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=Fable.Compiler&version=5.5.0
                    


                            Install as a Cake Tool

Fable: F# |> JS

Nuget Build Join the chat at https://gitter.im/fable-compiler/Fable

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Fable is an F# to JavaScript compiler powered FSharp Compiler Services, designed to make F# a first-class citizen of the JavaScript ecosystem. Check the website for more information and if you find the project useful, don't forget to give us a star!

Fable actually uses a fork of FCS with a few tweaks. Binaries are in lib/fcs folder. See this PR for more info.

Getting started

Check this page.

Building

Requirements

Use VSCode Dev Container

You can use VSCode Dev Container to get a preconfigured environment both with requirements and VSCode extensions.

  1. You need to have docker installed and running.
  2. Install the Dev Container extension in VSCode
  3. Open the project in VSCode and click on the green button in the bottom left corner.
Use your machine

Make sure the following requirements are installed in your system:

Build

Run ./build.sh or ./build.cmd to see the build options.

When using VSCode, you can also run the build tasks from the command palette (Ctrl+Shift+P) by typing Run Task and selecting the task you want to run.

We also configured several debug configurations that you can use from the debug panel (Ctrl+Shift+D). This is useful as you can attach the debugger to the Fable compiler process to check what's going on.

Contributing

Just by using Fable you're already contributing! You can help the community a lot by sharing examples and experiences in your personal (or Fable's) blog and/or by editing the Fable Resources page.

Send bug reports (ideally with minimal code to reproduce the problem) and feature requests to this GitHub repository. To interact with the community you can use the Gitter chat but please note maintainers are not checking the chat regularly.

If you are up to contribute a fix or a feature yourself, you're more than welcome! Please send first an issue or a minimal Work In Progess PR so we can discuss the implementation details in advance.

List of changelogs

Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  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. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (1)

Showing the top 1 NuGet packages that depend on Fable.Compiler:

Package Downloads
Fable.Plugins.NUnit

Package Description

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
5.5.0 18 6/30/2026
5.4.0 83 6/24/2026
5.3.0 1,011 6/16/2026
5.2.0 123 6/11/2026
5.1.0 121 5/28/2026
5.0.0 151 4/21/2026
5.0.0-rc.13 82 4/7/2026
5.0.0-rc.12 101 3/31/2026
5.0.0-rc.11 103 3/20/2026
5.0.0-rc.10 79 3/10/2026
5.0.0-rc.2 78 3/3/2026
5.0.0-rc.1 84 2/26/2026
5.0.0-alpha.23 90 2/13/2026
5.0.0-alpha.22 86 2/3/2026
5.0.0-alpha.21 106 12/26/2025
5.0.0-alpha.20 234 12/15/2025
5.0.0-alpha.19 399 12/8/2025
5.0.0-alpha.18 198 12/4/2025
5.0.0-alpha.17 666 12/3/2025
5.0.0-alpha.16 174 11/27/2025
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### 🚀 Features

* *(all)* Add `Compiler.is*` target detection flags for conditional branching (#4692) ([621dea31](https://github.com/fable-compiler/Fable/commit/621dea31daaef6a9dcf8a2ac5ceb144a063bb873))
* *(js/ts)* Map task { } to Promise<T> ([97f54d36](https://github.com/fable-compiler/Fable/commit/97f54d3692e5ba881c249b289c20b4fad5ac27e2))
* *(js/ts/python/beam)* Add support for `Async.AwaitEvent` (#4693) ([71c98179](https://github.com/fable-compiler/Fable/commit/71c981792b6ff99cd417bb2e70a13a9d55ed72cf))

### 🐞 Bug Fixes

* *(all)* Pass raw value for optional arguments of native bindings (#4688) ([a4c75483](https://github.com/fable-compiler/Fable/commit/a4c7548313fcbefc0ff0eddc7a95d8d0599d68a6))
* *(all)* Support .NET format specifiers and alignment in interpolated strings (#4695) ([7c50a3af](https://github.com/fable-compiler/Fable/commit/7c50a3af39aee935ce318f44e04247da32b33f0f))
* *(all)* Error on inline function referencing private value (#4701) ([cea6806e](https://github.com/fable-compiler/Fable/commit/cea6806ea388e73cf42fb673960f7862bb497fc2))
* *(beam)* Support module-level mutable variables via process dictionary (#4676) ([535b9af0](https://github.com/fable-compiler/Fable/commit/535b9af06969bcd7bdf118bdfb633ccadd5e4177))
* *(beam)* Namespace module-level mutable state keys by module (#4683) ([1ec28ab1](https://github.com/fable-compiler/Fable/commit/1ec28ab10923623eaf04b90bf8ffbeb54469d454))
* *(js)* Respect StringComparison in String.IndexOf/LastIndexOf (#4681) ([7cb92d52](https://github.com/fable-compiler/Fable/commit/7cb92d522e5dc8dfe51351565504c59a94c2f408))
* *(js/ts)* Implicit DateTime to DateTimeOffset conversion (#4697) ([fcbd9b91](https://github.com/fable-compiler/Fable/commit/fcbd9b91397a41226df4bed25c1bd1f0667efb64))
* *(js/ts)* Int list is not a union type (#4698) ([ecbecbe7](https://github.com/fable-compiler/Fable/commit/ecbecbe756610fd83a621c005e97eda92bbc332a))
* *(js/ts)* Hoist emitJsStatement imports with trailing comments (#4702) ([e820eb72](https://github.com/fable-compiler/Fable/commit/e820eb7239b2ffe0f2cb4bf3e6c040a1c7dca57f))
* *(js/ts)* Uncurry mutable module value alias calls (#4703) ([0de0d218](https://github.com/fable-compiler/Fable/commit/0de0d2187a68db0ac35bd2546dd98eb1c67397e5))
* *(js/ts)* Pass TypeInfo to getRecordFields to handle None fields in anonymous records (#4704) ([c977d78b](https://github.com/fable-compiler/Fable/commit/c977d78b39225a51c7bd051a1fe363ed0ccbe201))
* *(js/ts/python)* Drop allowAccessToPrivateRepresentation arg from reflection calls (#4689) ([ec3cded7](https://github.com/fable-compiler/Fable/commit/ec3cded78cc98dc740ce978d3bb078f2603f4846))
* *(python)* Fix task while loop stack overflow ([fdb0ec37](https://github.com/fable-compiler/Fable/commit/fdb0ec375e4464117470a528e427ee3df174f62a))
* *(ts)* Use declared type-param names in object expression generic methods (#4685) ([1c3e7d99](https://github.com/fable-compiler/Fable/commit/1c3e7d99653c7119c615b6dfd095a45e36add5b3))
* *(ts)* Use signature type-param names when implementing generic interface methods (#4686) ([03e5deee](https://github.com/fable-compiler/Fable/commit/03e5deeedaa35be2974f40e439e520526cf4c1ba))
* *(ts)* Bound enum-constrained type parameters with `extends number` (#4687) ([15daf624](https://github.com/fable-compiler/Fable/commit/15daf6245212ddb8b7ac6296631381711e34c98d))
* *(ts)* Widen isEnumDefined value parameter to accept any value (#4690) ([0d6498dd](https://github.com/fable-compiler/Fable/commit/0d6498ddf65e0e18918690633da23b04b78479f6))
* *(ts)* Keep enclosing type parameters in scope for nested members (#4691) ([f5723a2d](https://github.com/fable-compiler/Fable/commit/f5723a2d008408e1bca140256a452ac556c69c00))
* *(ts)* Re-declare class type params on generic static attached members (#4696) ([2da50780](https://github.com/fable-compiler/Fable/commit/2da50780b8254cfad05f3a645780f60999cae4ee))
* *(ts)* Filter class type params from attached let-binding methods (#4700) ([d3a6a1dd](https://github.com/fable-compiler/Fable/commit/d3a6a1dd09066b25d876e28446d70fea58162abd))

<strong><small>[View changes on Github](https://github.com/fable-compiler/Fable/compare/c9b3ee2429a4688946c1936e27df730837428070..c977d78b39225a51c7bd051a1fe363ed0ccbe201)</small></strong>