---
last_commit_released: c977d78b39225a51c7bd051a1fe363ed0ccbe201
include:
  - ../Fable.Core/
  - ../fable-standalone/
  - ../Fable.Transforms/
updaters:
  - package.json:
      file: package.json
---

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## 2.4.0 - 2026-06-30

### 🚀 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))

### 🐞 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)* 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))
* *(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)* 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>

## 2.3.0 - 2026-06-24

### 🚀 Features

* *(all)* Support Exception.InnerException across all targets (#4677) ([c9b3ee24](https://github.com/fable-compiler/Fable/commit/c9b3ee2429a4688946c1936e27df730837428070))

### 🐞 Bug Fixes

* *(beam)* Make immutable class instances process-portable (#4670) ([182eebef](https://github.com/fable-compiler/Fable/commit/182eebefacb58b7c72270c8d651936f87c3cbbcc))

<strong><small>[View changes on Github](https://github.com/fable-compiler/Fable/compare/477b8c693d948f74d8d2d5c38ac4d8e1f9287a51..c9b3ee2429a4688946c1936e27df730837428070)</small></strong>

## 2.2.0 - 2026-06-16

### 🚀 Features

* *(beam)* Add !^ erased-cast operator to BeamInterop (#4659) ([206776b](https://github.com/fable-compiler/Fable/commit/206776bfcc7068f9953bf6e70aafcc24c4082248))

### 🐞 Bug Fixes

* Add type specifiers to interpolated strings (#4646) ([512ae4d](https://github.com/fable-compiler/Fable/commit/512ae4d1901d6ed3c4c10bb5b4f99e73c49a2056))
* *(all)* Align `invalidArg` error message with .NET format (#4662) ([e672eb7](https://github.com/fable-compiler/Fable/commit/e672eb7ff6c38e15bada7520142024456b0dbb61))
* *(beam)* Preserve element type through Option.Value for interface dispatch (#4661) ([e5521b6](https://github.com/fable-compiler/Fable/commit/e5521b63f70ea25c3b42447ef4327f95245002da))
* *(python)* Emit wildcard default for union or-patterns (#4649) (#4653) ([c96f0ec](https://github.com/fable-compiler/Fable/commit/c96f0ecfe40d6be0fe8d95766ba279c3be4f6f7b))

<strong><small>[View changes on Github](https://github.com/fable-compiler/Fable/compare/15eb83ed36657f75073fb0e1b4cac677e24fc9bb..477b8c693d948f74d8d2d5c38ac4d8e1f9287a51)</small></strong>

## 2.1.0 - 2026-06-10

### 🚀 Features

* *(beam)* Support Erlang/BEAM target in standalone compiler (#4644) ([30310e4](https://github.com/fable-compiler/Fable/commit/30310e4f915443524cf5f2c1b326840ee556c7ae))

### 🐞 Bug Fixes

* *(beam)* Collapse array-literal process-dict ref round-trips in FFI/Emit calls (#4626) ([234ee08](https://github.com/fable-compiler/Fable/commit/234ee0846cf848dbad18d409c341755ad8d11da7))
* *(beam)* Make Emit $N substitution a single left-to-right pass (#4631) ([48af8db](https://github.com/fable-compiler/Fable/commit/48af8dba6a92d91115505c62f6a51c6aaa88ac19))
* *(js/ts)* Throw an error when trying to set non-property memeber inside of `jsOptions` (#4624) ([2d9673f](https://github.com/fable-compiler/Fable/commit/2d9673fb609f6ae3273576c913929e0f601d8f5d))
* *(python)* Avoid union case field name collision with Union.name (#4647) ([ff5df24](https://github.com/fable-compiler/Fable/commit/ff5df24191a1b3aef5c86efa25f87fa69b3462d9))
* *(python)* Make [<AttachMembers>] union static members work (#4634) (#4636) ([15eb83e](https://github.com/fable-compiler/Fable/commit/15eb83ed36657f75073fb0e1b4cac677e24fc9bb))

<strong><small>[View changes on Github](https://github.com/fable-compiler/Fable/compare/63bcd3d90f37cb3934edcc59b5f54f49ffab3896..15eb83ed36657f75073fb0e1b4cac677e24fc9bb)</small></strong>

## 2.0.1 - 2026-05-28

### 🐞 Bug Fixes

* [JS/TS/Tests] Remove mocha to resolve package vulnerabilities (#4604) ([092324b](https://github.com/fable-compiler/Fable/commit/092324b55d17973ef8364c00d4ed48eb067c0f23))
* [Rust] Update hashing and datetime tests (#4613) ([9d39037](https://github.com/fable-compiler/Fable/commit/9d390376fd2c81f76fde70c522b59f61a9c9175d))
* *(all)* Duplicate LetRec bindings during inline expansion (#4592) ([62612a5](https://github.com/fable-compiler/Fable/commit/62612a5bb42644934b7573b7cf8f9db930c5dc37))
* *(all)* Fix super call in multi-level generic class hierarchy using wrong mangled name (#4414) ([db1d4d2](https://github.com/fable-compiler/Fable/commit/db1d4d2e8cdbb9d5a16856c91192c1f0fab3f783))
* *(js/ts)* Fix JSX props with long string values causing compile error (fixes #3839) (#4545) ([d828a46](https://github.com/fable-compiler/Fable/commit/d828a461797e3f33bf4ab99b46030d16b29771e6))
* *(js/ts)* Add support for `match` clauses in `JSX.create` (#4620) ([616edca](https://github.com/fable-compiler/Fable/commit/616edca568890549ff81cfa18ab32ca0b807c8eb))
* *(js/ts)* Don't spread last arg in String.Concat call (#4621) ([3de580e](https://github.com/fable-compiler/Fable/commit/3de580e4447ed0090a79648caa8f1e5003bac91d))
* *(js/ts)* Inline AttachMembers members at call sites (#4622) ([63bcd3d](https://github.com/fable-compiler/Fable/commit/63bcd3d90f37cb3934edcc59b5f54f49ffab3896))
* *(python)* Avoid duplicate captured argument in hoisted guards (#4610) (#4611) ([90aec48](https://github.com/fable-compiler/Fable/commit/90aec483296d26549aedf9eaf46f0825d70a4022))

<strong><small>[View changes on Github](https://github.com/fable-compiler/Fable/compare/b471dc16fc3b5132af77b5974d1669c9b8220cca..63bcd3d90f37cb3934edcc59b5f54f49ffab3896)</small></strong>

## 2.0.0 - 2025-04-21

* Fable 5

## 2.0.0-rc.1 - 2025-02-26

* Fable 5.0.0-rc.1

## 2.0.0-beta.1 - 2025-02-16

* Fable 5.0.0-alpha.10
* Replace `FABLE_COMPILER_4` with `FABLE_COMPILER_5` as the compiler directive

## 1.2.2 - 2024-05-24

### Fixed

* Fixed includes to come from this package internals (by @MangelMaxime)

## 1.2.1 - 2024-05-24

### Fixed

* Fixed includes to come from this package internals and to use `fable-library-js` instead of `fable-library-ts` (by @ncave)

## 1.2.0 - 2024-05-23

### Changed

* Use `@fable-org/fable-metadata` package instead of `fable-metadata` (by @MangelMaxime)
* Use `@fable-org/fable-standalone` package instead of `fable-standalone` (by @MangelMaxime)
* Make `GetDirectoryName` return `"."` instead of `""` if the path doesn't contain any directory (by @MangelMaxime)

### Fixed

* Fix initialization of `fable-standalone` with the new package format (by @MangelMaxime)

## 1.1.0 - 2024-02-20

* Add `NPM_PACKAGE_FABLE_COMPILER_JAVASCRIPT` compiler directive (by @MangelMaxime)

## 1.0.0 - 2024-02-12

* Release stable version

## 1.0.0-beta-001 - 2024-02-12

### Added

* First release as part of `@fable-org` scope