Changelog

Tags:

💥 [Breaking Change]

👓 [Spec Compliance]

🚀 [New Feature]

🐛 [Bug Fix]

📝 [Documentation]

🏠 [Internal]

💅 [Polish]

12.0.0-alpha.7 (Unreleased)

🏠 Internal

AST cleanup: use inline record for Pexp_fun. #7213

💅 Polish

Add all standard CSS properties to JsxDOMStyle. #7205

12.0.0-alpha.6

🚀 New Feature

Add Option.all & Result.all helpers. #7181
Add @react.componentWithProps for React component functions taking a props record instead of labeled arguments. #7203

🐛 Bug fix

Fix exponential notation syntax. #7174
Fix bug where a ref assignment is moved ouside a conditional. #7176
Fix nullable to opt conversion. #7193
Raise error when defining external React components with @react.componentWithProps. #7217

🏠 Internal

Use latest compiler for tests. #7186
Added infra to modernise AST: theres' Parsetree, Parsetree0 (legacy), and conversion functions to keep compatibility with PPX. #7185
AST cleanup: remove exp object and exp unreachable. #7189
AST cleanup: explicit representation for optional record fields in types. #7190 #7191
AST cleanup: first-class expression and patterns for records with optional fields. #7192
AST cleanup: Represent the arity of uncurried function definitions directly in the AST. #7197
AST cleanup: Remove Pexp_function from the AST. #7198
Remove unused code from Location and Rescript_cpp modules. #7150
Build with OCaml 5.2.1. #7201
AST cleanup: Remove Function$ entirely for function definitions. #7200
AST cleanup: store arity in function type. #7195
AST cleanup: remove explicit uses of function$ in preparation for removing the type entirely. #7206
AST cleanup: remove function$ entirely. #7208

12.0.0-alpha.5

🚀 New Feature

Introduce "Unified operators" for arithmetic operators (+, -, *, /, mod). #7057
Add remainder (%, aka modulus) operator. #7152

🐛 Bug fix

Fix and clean up boolean and/or optimizations. #7134 #7151
Fix identifiers with name arguments and eval to be mangled. #7163

💅 Polish

Improve code generation for pattern matching of untagged variants. #7128
Improve negation handling in combination with and/or to simplify generated code (especially coming out of pattern matching). #7138
Optimize JavaScript code generation by using x == null checks and improving type-based optimizations for string/number literals. #7141
Improve pattern matching on optional fields. #7143 #7144
Optimize compilation of switch statements for untagged variants when there are no literal cases. #7135
Further improve boolean optimizations. #7149
Simplify code generated for conditionals. #7151

🏠 Internal

Move rescript-editor-analysis and rescript-tools into compiler repo. #7000

12.0.0-alpha.4

💥 Breaking Change

OCaml compatibility in the stdlib and primitives are dropped/deprecated. #6984
Remove JSX v3. #7072
Remove js_cast.res. #7075

🚀 New Feature

Use FORCE_COLOR environmental variable to force colorized output. #7033
Allow spreads of variants in patterns (| ...someVariant as v => ) when the variant spread is a subtype of the variant matched on. #6721
Fix the issue where dynamic imports are not working for function-defined externals. #7060
Allow pattern matching on dicts. switch someDict { | dict{"one": 1} => Js.log("one is one") }. #7059
"ReScript Core" standard library is now included in the rescript npm package. #7108 #7116
Handle absolute filepaths in gentype. #7104

🐛 Bug fix

Fix tuple coercion. #7024
Fix attribute printing. #7025
Fix "rescript format" with many files. #7081
Fix bigint max, min. #7088
Fix parsing issue with nested variant pattern type spreads. #7080
Fix JSX settings inheritance: only 'version' propagates to dependencies, preserving their 'mode' and 'module'. #7094
Fix variant cast to int. #7058
Fix comments formatted away in function without arguments. #7095
Fix genType JSX component compilation. #7107

💅 Polish

Add some context to error message for unused variables. #7050
Improve error message when passing children prop to a component that doesn't accept it. #7044
Improve error messages for pattern matching on option vs non-option, and vice versa. #7035
Improve bigint literal comparison. #7029
Improve output of @variadic bindings. #7030
Improve error messages around JSX components. #7038
Improve output of record copying. #7043
Provide additional context in error message when unit is expected. #7045
Improve error message when passing an object where a record is expected. #7101

🏠 Internal

Remove uncurried flag from bsb. #7049
Build runtime/stdlib files with rescript/bsb instead of ninja.js. #7063
Build tests with bsb and move them out of jscomp. #7068
Run build_tests on Windows. #7065
Rename folder "jscomp" to "compiler". #7086
Disable -bs-cross-module-opt for tests. #7071
Move ounit_tests into the tests folder. #7096
Move syntax_tests into the tests folder. #7090 #7097
Capitalize runtime filenames. #7110
Build mocha tests as esmodule / .mjs. #7115
Use dict instead of Dict.t everywhere. #7136

12.0.0-alpha.3

🐛 Bug fix

Revert "Throws an instance of JavaScript's new Error() and adds the extension payload for cause option" (#6611). #7016
Fix dict literals error. #7019

12.0.0-alpha.2

🚀 New Feature

Allow coercing polyvariants to variants when we can guarantee that the runtime representation matches. #6981
Add new dict literal syntax (dict{"foo": "bar"}). #6774
Optimize usage of the new dict literal syntax to emit an actual JS object literal. #6538

🐛 Bug Fix

Fix issue where long layout break added a trailing comma in partial application .... #6949
Fix incorrect format of function under unary operator. #6953
Fix incorrect printing of module binding with signature. #6963
Fix incorrect printing of external with @as attribute and _ placholder (fixed argument). #6970
Disallow spreading anything but regular variants inside of other variants. #6980
Fix comment removed when function signature has type keyword. #6997
Fix parse error on doc comment before "and" in type def. #7001

🏠 Internal

Add dev container. #6962
Convert more tests to the node test runner. #6956
Remove attribute "internal.arity". #7004
Remove dead modules. #7008

💅 Polish

Improve formatting in the generated js code. #6932
- }\ncatch{ -> } catch {
- for(let i = 0 ,i_finish = r.length; i < i_finish; ++i){ -> for (let i = 0, i_finish = r.length; i < i_finish; ++i) {
- while(true) { -> while (true) {
- Fixed tabulation for switch case bodies
- Fixed tabulation for throw new Error bodies
- Removed empty line at the end of switch statement
- Removed empty default case from switch statement in the generated code
Optimised the Type Extension runtime code and removed trailing /1 from RE_EXN_ID. #6958
Compact output for anonymous functions. #6945 #7013
Rewatch 1.0.9. #7010

12.0.0-alpha.1

🚀 New Feature

Allow @directive on functions for emitting function level directive code (let serverAction = @directive("'use server'") (~name) => {...}). #6756
Add rewatch to the npm package as an alternative build tool. #6762
Throws an instance of JavaScript's new Error() and adds the extension payload for cause option. #6611
Allow free vars in types for type coercion e :> t. #6828
Allow private in with constraints. #6843
Add regex literals as syntax sugar for @bs.re. #6776
Improved mechanism to determine arity of externals, which is consistent however the type is written. #6874 #6881 #6883
Add Js.globalThis object binding. #6909

💥 Breaking Change

Make j and js allowed names for tag functions. #6817
lazy syntax is no longer supported. If you're using it, use Lazy module or React.lazy_ instead. #6342
Remove handling of attributes with bs. prefix (@bs.as -> @as etc.). #6643
Remove obsolete @bs.open feature. #6629
Drop Node.js version <18 support, due to it reaching End-of-Life. #6429
Remove deprecated -bs-super-errors option. #6814
Some global names and old keywords are no longer prefixed. #6831
Remove ml parsing tests and conversion from .ml to .res via format. #6848
Remove support for compiling .ml files, and general cleanup. #6852
Remove rescript convert subcommand. #6860
Remove support for @bs.send.pipe. This also removes all functions in Js_typed_array that rely on @bs.send.pipe. #6858 #6891
Remove deprecated Js.Vector and Js.List. #6900
Remove support for %time extension. #6924
Remove caml_external_polyfill module and the related behavior. #6925

🐛 Bug Fix

Fix unhandled cases for exotic idents (allow to use exotic PascalCased identifiers for types). #6777 #6779 #6897
Fix unused attribute check for @as. #6795
Reactivate unused attribute check for @int. #6802
Fix issue where using partial application ... can generate code that uses Curry at runtime. #6872
Avoid generation of Curry with reverse application |>. #6876
Fix issue where the internal ppx for pipe -> would not use uncurried application in uncurried mode. #6878

🏠 Internal

Build with OCaml 5.2.0. #6797
Convert OCaml codebase to snake case style. #6702
Fix -nostdlib internal compiler option. #6824
Remove a number of ast nodes never populated by the .res parser, and resulting dead code. #6830
Remove coercion with 2 types from internal representation. Coercion e : t1 :> t2 was only supported in .ml syntax and never by the .res parser. #6829
Convert caml_format and js_math to .res. #6834
Convert js.ml files to .res. #6835
Remove old .ml tests. #6847
Make compiler libs ready for uncurried mode. #6861
Make tests ready for uncurried mode. #6862
Make gentype tests uncurried. #6866
Remove @@uncurried.swap, which was used for internal tests. #6875
Build the compiler libraries/tests in uncurried mode. #6864
Ignore -uncurried command-line flag. #6885
Cleanup: remove tracking of uncurried state in parser/printer. #6888
Remove %opaque primitive. #6892
Reunify JsxC/JsxU -> Jsx etc. #6895
Remove the transformation of foo(1,2) into Js.Internal.opaqueFullApply(Internal.opaque(f), 1, 2), and change the back-end to treat all applications as uncurried. #6893
Remove @uncurry from ReScript sources (others, tests). #6938
Remove leftover uncurried handling. #6939 #6940
Start converting tests from mocha to the node test runner. #6956

💅 Polish

Make the --help arg be prioritized in the CLI, so correctly prints help message and skip other commands. #6667
Remove redundant space for empty return in generated js code. #6745
Remove redundant space for export in generated js code. #6560
Remove redundant space after continue in generated js code. #6743
Remove empty export blocks in generated js code. #6744
Fix indent for returned/thrown/wrapped in parentheses objects in generated js code. #6746
Fix indent in generated js code. #6747
In generated code, use let instead of var. #6102
Turn off transformation for closures inside loops when capturing loop variables, now that let is emitted instead of var. #6480
Improve unused attribute warning message. #6787
Remove internal option use-stdlib from build schema. #6778
Fix Js.Types.JSBigInt payload to use native bigint type. #6911
Deprecate %external extension, which has never been officially introduced. #6906
Deprecate xxxU functions in Belt. #6941
Improve error messages for function arity errors. #6990
Add missing HTML attribute capture to JsxDOM.res. #7006

11.1.3

🐛 Bug Fix

Fix tag function location on compiler error. #6816
Fix Deno compatibility issues on Windows. #6850
Fix issue with infinite loops with type errors on recursive types. #6867
Ignore @uncurry attribute in uncurried mode, to avoid generating calls to Curry at runtime. #6869
Avoid generating calls to Curry when adjusting arity of uncurried functions. #6870
Fix build after calling without -warn-error, see #6868 for more details. #6877
Fix issue with uninitialized _param in recursive functions with unit argument. #6907

11.1.3-rc.1

🐛 Bug Fix

Omit standard library dir from load path if -nostdlib is set. #6833

11.1.2

🐛 Bug Fix

Fix issue where capitalised type variables were only allowed in certain positions. #6820

11.1.2-rc.1

🚀 New Feature

Support Windows 11 ARM (using the x64 binaries in emulation). #6813

🐛 Bug Fix

Fix location of let bindings with attributes. #6791
PPX v4: mark props type in externals as @live to avoid dead code warnings for prop fields in the editor tooling. #6796
Fix issue where optional labels were not taken into account when disambiguating record value construction. #6798
Fix issue in gentype when type Jsx.element surfaces to the user. #6808
Fix inclusion check (impl vs interface) for untagged variants, and fix the outcome printer to show tags. #6669
Fix encoding inside tagged template literals. #6810

11.1.1

🐛 Bug Fix

Fix issue of incorrect switch cases with identical bodies when mixing object and array. #6792
Fix formatter eats comments on the first argument of a uncurried function. #6763
Fix formatter removes parens in pipe operator with anonymous uncurried function. #6766

11.1.0

🐛 Bug Fix

Revert escape JSX prop names with hyphens (#6705). #6731

11.1.0-rc.8

🚀 New Feature

Add %todo extension for leaving implementation for later. #6713
Add -warn-error argument for generating errors in CI. Useful for %todo extension. #6717

🐛 Bug Fix

Improve error when using @deriving(accessors) on a variant with record arguments. #6712
Stop escaping JSX prop names with hyphens. #6705
Fix trailing undefined for optional parameters not omitted with @send and @new. #6716
Fix JSX4 adding the incorrect type annotation for the prop ref in React.forwardRef component. #6718
Fix description for warning number 110. #6725

💅 Polish

Module spec es6 and es6-global is deprecated in favor of esmodule. #6709

11.1.0-rc.7

🐛 Bug Fix

Fix variance setting for builtin dict type. Fixes issues around inference. #6707

11.1.0-rc.6

🚀 New Feature

Add experimental BigInt support. #6670, #6696

🐛 Bug Fix

Fix mishandling of uncurried functions in super errors. #6694

11.1.0-rc.5

🐛 Bug Fix

Fix misparsing in/after JSX. #6686
Fix @deriving(accessors) outputting curried functions in uncurried mode. #6687

11.1.0-rc.4

🐛 Bug Fix

Fix emitting static import instead of dynamic import. #6664
Fix local type variables breaking react components. #6665
Fix remove redundant branches in generated switch body. #6672
Fix issue in partial application when the last named arg is provided. #6681

:nail-care: Polish

Omit undefined in external function calls for trailing optional arguments when not supplied. #6653
Make pattern match suggestions to be easier to copy-paste. #6656

11.1.0-rc.3

💅 Polish

No parens around tagged template literals. #6639
Allow identifier with modules in tagged template literals (e.g. Pg.sqlselect * from ${table} where id = ${id}). #6645

🐛 Bug Fix

Fix compiler crash when reexporting tagged template literal externals. #6645

11.1.0-rc.2

🚀 New Feature

Add support for array spread. #6608
Support import attributes (https://github.com/tc39/proposal-import-attributes) in @module(). #6599
allow hyphens in jsx tag names (e.g. <mj-column>). #6609

🐛 Bug Fix

Fix issue with async and newtype in uncurried mode. #6601
Generic JSX transform: Rename expected module name for lowercase JSX to Elements from DOM. #6606
Generic JSX transform: Set default config params for jsxConfig. #6606
Generic JSX transform: Handle namespaced names. #6606
Fix issue with doc comment in recursive module. #6613
Fix issue with Exceptions and Extensible types runtime generation. #6570
Fix inline comment before spread syntax in record. #6615

🏠 Internal

Use OCaml 4.14.1 (+ Alpine 3.19 container) for CI build. #6600

11.1.0-rc.1

🚀 New Feature

Experimental support of tagged template literals, e.g. sql`select * from ${table}. #6250
Experimental support for generic/custom JSX transforms. #6565
dict is now a builtin type. #6590

🐛 Bug Fix

GenType: distinguish inline records from unary variant cases of object type. #6586

11.0.1

🐛 Bug Fix

Renamed inline record fields: fix renamed field access in inline records. #6551
Fixed issue with coercions sometimes raising a Not_found instead of giving a proper error message. #6574
Fix issue with recursive modules and uncurried. #6575

💅 Polish

Improve error message for missing label(s) in function application. #6576

11.0.0

No changes compared to rc.9.

11.0.0-rc.9

🚀 New Feature

GenType: support @deriving(accessors) outputs. #6537
Allow coercing ints and floats to unboxed variants that have a catch-all unboxed int or float case. #6540
Allow tuples in untagged variants. #6550

🐛 Bug Fix

GenType: now emits full suffix on JS import path to be compatible with .res.js. #6541

💅 Polish

Format docstrings. #6417
JSX v4: make automatic mode the default. #6552

11.0.0-rc.8

🚀 New Feature

Add support for type coercion for invariant type arguments such as array payloads. #6518
Start treating rescript command the same as the rescript build command, so now you can do rescript -w. #6524

🐛 Bug Fix

Fix accidental removal of Belt.Result.Ok and Belt.Result.Error constructors in rc.5. #6514
Add missing check that the runtime representation of variants matches implementation and interface. https://github.com/rescript-lang/rescript-compiler/pull/6513/files
GenType: only export types (not values) from module types. #6516
Fix compiler crash with unboxed variant definition with only 1 constructor. #6523
GenType: support mutual recursive types inside modules. #6528
Workaround for @as in labels in uncurried externals, which was broken. #6527

💅 Polish

GenType: make outputs DCE-friendly. #6508

11.0.0-rc.7

🚀 New Feature

Allow empty inline records in variants. #6494
Allow empty record patterns in pattern matching. #6494

🐛 Bug Fix

Fix issue where an inline record with attributes did not parse. #6499
Fix issue with uncurried function with 1 arg being a variable where an undefined variable could be emitted. #6507
Fix runtime errors on @genType.as("alias") output. #6509

11.0.0-rc.6

🚀 New Feature

Freely configurable suffix for generated .js files. #6472

🐛 Bug Fix

Fix issue with GenType and result introduced in rc.5. #6464
Fix compiler crash when inlining complex constants in pattern matching. #6471
Fix issue with generating async functions inside loops. #6479
Fix issue with Gentype and string annotations with numbers such as @as("0"). #6487
Fix error message on curried/uncurried signature mismatch. #6414

💅 Polish

Improve some error messages in rescript.conf parsing. #6469

11.0.0-rc.5

🚀 New Feature

Allow coercing unboxed variants with only strings (now including with a single payload of string) to the primitive string. #6441
Allow coercing strings to unboxed variants that have a catch-all unboxed string case. #6443
Allow coercing int to float. #6448

🐛 Bug Fix

Fix issue with dynamic import of module in nested expressions. #6431
Fix issue where GenType was not supporting @tag on ordinary variants. #6437
Fix using dynamic import of module in block instead of async function. #6434
Fix issue with using dynamic import of module in uncurried mode. #6434
Fix build error with JSX v4 transformation of React.forwardRef in uncurried mode. #6447
Fix printing of exotic JSX names. #6451
Fix locations when code with await fails to compile (all locations would point to the internal function unsafe_await). #6452
Fix renaming fields (with @as) in inline records doesn't work when destructuring. #6456
Fix rc.4 regressions:
- Don't show compilation time when calling rescript build -help command. #6439
- Running rescript build -w with a compilation error doesn't exit with an error code and continues waiting for changes. #6460

🏠 Internal

Remove dependency stdlib-406 -> belt. #6453
Playground: Add support for implicitly opened modules. #6446

💅 Polish

Add Deno to reserved names, so that modules named Deno don't clash with the globally exposed Deno object. #6428
Disable ESLint/TSLint on gentype outputs properly. #6442
Improve rescript CLI to use stdout/stderr appropriately for help command's message. #6439
Generate f() instead of f(undefined) for f(). #6459

11.0.0-rc.4

🚀 New Feature

Support renaming fields in inline records with @as attribute. #6391
Support renaming object fields of @obj external ppx with @as attribute. #6391
Add builtin abstract types for File and Blob APIs. #6383
Untagged variants: Support promise, RegExes, Dates, File and Blob. #6383
Untagged variants: Support bool. #6368
Support aliased types as payloads to untagged variants. #6394
Support the async component for React Server Component in JSX V4. #6399
Support rescript.json configuration file and deprecate bsconfig.json. #6382

💥 Breaking Change

Update watcher rules to recompile only on config and *.res/*.resi/*.ml/.mli file changes. Solves the issue of unnecessary recompiles on .css, .ts, and other unrelated file changes. #6420
Add smart printer for pipe chains. #6411 (the formatter will reformat existing code in certain cases)
Js.Json.t now uses Boolean(bool) instead of explicit @as(true) True | @as(false) False. #6421

🐛 Bug Fix

Fix issue with GenType and labelled arguments. #6406
Fix dependencies reinitialization on every change in watch mode. Leads to faster rebuilds and cleaner terminal. #6404

💅 Polish

A little performance improvement for JSX V4 runtime helper by removing one object allocation for components with key prop. #6376
The error message for "toplevel expressions should evaluate to unit" has been revamped and improved. #6407
Improve "Somewhere wanted" error messages by changing wording and adding more context + suggested solutions to the error messages where appropriate. #6410
Display the compile time for rescript build command. #6404
Improve help message for build and clean commands. #6404
Pass through the -verbose flag to builds in watch mode. #6404
Improve error message when defining duplicate labels in a record. #6415
Improve error message when trying to concatenate strings using the wrong operator. #6416

11.0.0-rc.3

🐛 Bug Fix

Fix issue with JSX V4 when component props have the default value with same name. #6377
Fixed code formatter with "uncurried": false in bsconfig. #6378

💅 Polish

Add Bun to reserved names, so that modules named Bun don't clash with the globally exposed Bun object. #6381

11.0.0-rc.2

🚀 New Feature

rescript build will always build its dependency by default. The argument -with-deps is not needed anymore. #6350

💥 Breaking Change

Stop mangling object field names. If you had objects with field names containing "__" or leading "_", they won't be mangled in the compiled JavaScript and represented as it is without changes. #6354

🐛 Bug Fix

Fixed outcome printer resolution of uncurried config. #6353

11.0.0-rc.1

🚀 New Feature

GenType: Propagate comments from record fields to emitted TypeScript types. #6333

💥 Breaking Change

$$default is no longer exported from the generated JavaScript when using default exports. #6328

💅 Polish

Conditionally print error message about record with missing label potentially being a component. #6337
Put definition in the bottom and the actual error at the top when reporting errors for supplying fields etc with the wrong name. #6336
Fix left over places where polyvariant tag names were printed in OCaml syntax instead of ReScript. #6348

11.0.0-beta.4

🚀 New Feature

Variants: Allow coercing from variant to variant where applicable. #6314
Variants: Experimental support for spreading variant type definitions to copy constructors from one variant to another. #6316

💥 Breaking Change

Fixed name collision between the newly defined Js.Json.t and the variant constructor in the existing Js.Json.kind type. To address this, the usage of the existing Js.Json.kind type can be updated to Js.Json.Kind.t. #6317

🐛 Bug Fix

Fixed outcome printing of uncurried higher order function types. #6323
Fixed printing of type constraints in template literal substitutions. #6324

11.0.0-beta.3

🚀 New Feature

Untagged variants: consider regexp as an object type. #6296
Semantic-based optimization of code generated for untagged variants. #6108
Record type spreads: Allow using type variables in type spreads. Both uninstantiated and instantiated ones. #6309
Variants: Allow coercing variants to string/int/float when applicable. #6311

🐛 Bug Fix

Fix issue with dynamic import of modules in expressions. #6310

11.0.0-beta.2

🚀 New Feature

Introduced a new %ffi extension (experimental - not for production use!) that provides a more robust mechanism for JavaScript function interoperation by considering function arity in type constraints. This enhancement improves safety when dealing with JavaScript functions by enforcing type constraints based on the arity of the function. #6251
Extended untagged variants with function types. #6279

💥 Breaking Change

Remove rudimentary node bindings and undocumented %node extension. #6285

🐛 Bug Fix

Fix issue where uncurried type internals leak in type error. #6264
Improve error messages for untagged variant definition. #6290
Fix type checking performance issue for large records. #6289

11.0.0-beta.1

🚀 Main New Feature

Make uncurried mode opt-out: by default, every project is now in uncurried mode, unless "uncurried": false is specified in the project config. #6249

💅 Polish

Removed duplicate Super_error implementation in syntax. #6246

🐛 Bug Fix

Fix issue with inlining records in the presence of record coercion. #6256

11.0.0-alpha.6

💥 Breaking Change

-bs-super-errors flag has been deprecated along with Super_errors. #6243
@rescript/react >= 0.12.0-alpha.2 is now required because of the React.fragment's children type fix. #6238

🐛 Bug Fix

Remove unnecessary require and import statements when using dynamic imports. #6232
Fix option unboxing logic in the presence of untagged variants. #6233
Fix printing of local module with type. #6212
Adapting JSX4 to React.fragment's children type change ('children -> React.element) #6238

💅 Polish

In uncurried mode, outcome printer swaps curried and uncurries function printing compared to legacy.
Add location information to duplicate type definition error messages. #6199
Replace normal module errors with Super_error module, and clean up Super_error. #6199
Js.Json.t, Js.null and Js.nullable are now untagged variants representing their runtime values, instead of abstract types. #6218

11.0.0-alpha.5

🚀 Main New Feature

Add support for Dynamic import. #5703
GenType: Add moduleResolution option to customize extensions on emitted import statements. This helps to adjust output compatibility with TypeScript projects using ESM. #6182
- node (default): Drop extensions.
- node16: Use TS output's extensions. Make it ESM-compatible.
- bundler: Use TS input's extensions. Make it ESM-compatible.
Make untagged variants understand payloads defined as records. #6208

💥 Breaking Change

Parse assert as a regular function. assert is no longer a unary expression. Example: before assert 1 == 2 is parsed as (assert 1) == 2, now it is parsed as assert(1 == 2). #6180

🐛 Bug Fix

Make "rescript format" work with node 10 again and set minimum required node version to 10 in package.json. #6186
Fix partial application for uncurried functions with labeled args #6198
Add error messages for dangling doc comments/attributes and mutable in record type definition. #6206
Fix issue with overlapping array and object in untagged variants #6219

11.0.0-alpha.4

🚀 Main New Feature

Add surface syntax for partial application of uncurried functions: foo(1, ...). This corresponds to curried application in the old mode. #6166

🐛 Bug Fix

Fix broken formatting in uncurried mode for functions with _ placeholder args. #6148
Fix issue where spreading record types with optional labels would not have their labels preserved as optional. #6154
Fix error location to be the type with the spreads when spreading record types with duplicate labels. #6157
Disable warning on @inline attibute on uncurried functions. #6152
Support doc comments on arguments of function types. #6161
Fix issue with record type coercion and unboxed. #6158
Fixed subtype checking for record types with "@as" attributes: The subtype relationship now takes into account the compatibility of "@as" attributes between corresponding fields, ensuring correctness in runtime representation. #6158
Emit directive above header comment. #6172
Add error message to private extension. #6175

💅 Polish

Update list of reserved JS keywords. #6167
Add error message to @@directive. #6174

11.0.0-alpha.3

🚀 Main New Feature

Add support for extensible records (e.g. type t = {...t1, x:int, ...t2}) #5715

🐛 Bug Fix

Fix formatting and parentheses placement in uncurried functions with constraints. #6143

11.0.0-alpha.2

🚀 Main New Feature

Add support for type coercion :> for records. #5721

🐛 Bug Fix

Special case generation of uncurried functions with 1 argument of unit type so they don't take a parameter. #6131

11.0.0-alpha.1

🚀 Main New Feature

Introduce experimental uncurried mode. For experimentation only. PR #5796
Customization of runtime representation of variants and introduction of untagged variants PR #6095, PR #6103

🚀 New Feature

Add support for uncurried mode: a mode where everything is considered uncurried, whether with or without the .. This can be turned on with @@uncurried locally in a file. For project-level configuration in bsconfig.json, there's a boolean config "uncurried", which propagates to dependencies, to turn on uncurried mode. Since there's no syntax for partial application in this new mode, introduce @res.partial foo(x) to express partial application. This is temporary and will later have some surface syntax. Make uncurried functions a subtype of curried functions, and allow application for uncurried functions. The make function of components is generated as an uncurried function. Use best effort to determine the config when formatting a file. #5968 #6080 #6086 #6087
Customization of runtime representation of variants. This is work in progress. E.g. some restrictions on the input. See comments of the form "TODO: put restriction on the variant definitions allowed, to make sure this never happens". #6095
Introduce untagged variants #6103
Add support for unary uncurried pipe in uncurried mode #5804
Add support for partial application of uncurried functions: with uncurried application one can provide a subset of the arguments, and return a curried type with the remaining ones #5805
Add support for uncurried externals #5815 #5819 #5830 #5894
Parser/Printer: unify uncurried functions of arity 0, and of arity 1 taking unit. There's now only arity 1 in the source language. #5825
Add support for default arguments in uncurried functions #5835
Inline uncurried application when it is safe #5847
Support optional named arguments without a final unit in uncurried functions #5907
GenType: add the option to use the @genType annotation at the module level, meaning that all the items in the module should be exported. #6113
GenType: add support for @genType annotations on module definitions. #6113
Prebuilt binaries are now provided for all major platforms:
- macOS x64
- macOS ARM
- Linux x64 (statically linked)
- Linux ARM (statically linked)
- Windows x64

💥 Breaking Change

Remove support for the legacy Reason syntax. Existing Reason code can be converted to ReScript syntax using ReScript 9 as follows:
- npm i -g rescript@9
- rescript convert <reason files>
Remove obsolete built-in project templates and the "rescript init" functionality. This is replaced by create-rescript-app which is maintained separately.
Do not attempt to build ReScript from source on npm postinstall for platforms without prebuilt binaries anymore.
Made pinned dependencies transitive: if a is a pinned dependency of b and b is a pinned dependency of c, then a is implicitly a pinned dependency of c. This change is only breaking if your build process assumes non-transitivity.
Curried after uncurried is not fused anymore: (. x) => y => 3 is not equivalent to (. x, y) => 3 anymore. It's instead equivalent to (. x) => { y => 3 }. Also, (. int) => string => bool is not equivalen to (. int, string) => bool anymore. These are only breaking changes for unformatted code.
Exponentiation operator ** is now right-associative. 2. ** 3. ** 2. now compile to Math.pow(2, Math.pow(3, 2)) and not anymore Math.pow(Math.pow(2, 3), 2). Parentheses can be used to change precedence.
Remove unsafe j`$(a)$(b)` interpolation deprecated in compiler version 10 #6068
Remove deprecated module Printexc
@deriving(jsConverter) not supported anymore for variant types #6088
New representation for variants, where the tag is a string instead of a number. #6088
GenType: removed support for @genType.as for records and variants which has become unnecessary. Use the language's @as instead to channge the runtime representation without requiring any runtime conversion during FFI. #6099 #6101

🐛 Bug Fix

Fix issue where uncurried was not supported with pipe #5803
Fix printing of nested types in uncurried mode #5826
Fix issue in printing uncurried callbacks #5828
Fix formatting uncurried functions with attributes #5829
Fix parsing/printing uncurried functions with type parameters #5849
Fix compiler ppx issue when combining async and uncurried application #5856
Fix issue where the internal representation of uncurried types would leak when a non-function is applied in a curried way #5892
Fix some comments disappearing in array access expressions #5947
Parser: fix location of variable when function definition {v => ...} is enclosed in braces #5949
Fix issue with error messages for uncurried functions where expected and given type were swapped #5973
Fix issue with integer overflow check #6028
Make internal encoding of locations aware of unicode #6073
Fix issue where foo(x,_) in uncurried mode would generate a curried function #6082
Fix printing of uncurried application when the lhs is a function definition #6084
Fix parsing uncurried type starting with path #6089
Fix bigInt comparison #6097
Fixed a bug where the async attribute was not preserved when using the @this decorator in ReScript functions. This fix allows proper handling of async functions with the @this decorator. Issue: #6100
Fix issue with GenType and module aliases #6112

💅 Polish

Syntax: process uncurried types explicitly in the parser/printer #5784 #5822
Syntax: process uncurried function declarations explicitly in the parser/printer #5794
PPX V4: allow uncurried make function and treat it like a curried one #5802 #5808 #5812
Remove processing of objects expressions, which don't exist in .res syntax (Pexp_object) #5841
Remove class type processing from compiler ppx #5842
Remove method application via operator ##, which does not exist in .res syntax #5844
Treat @meth annotation as making the type uncurried for backwards compatibitly with some examples #5845
Process @set annotation for field update as generating an uncurried function #5846
Treat uncurried application of primitives like curried application, which produces better output #5851
New internal representation for uncurried functions using built-in type function$<fun_type, arity> this avoids having to declare all the possible arities ahead of time #5870
PPX V3: allow uncurried make function and treat it like a curried one #6081
Add support for |> in uncurried mode by desugaring it #6083
Change the compilation of pattern matching for variants so it does not depends on variats being integers #6085
Improve code generated for string templates #6090
Move Jsx and JsxDOM and JsxEvent and JsxPPXReactSupport inside Pervasives and build them separately for curried and uncurried mode #6091
Gentype: allow recursive data types rescript-association/genType#585

10.1.4

🐛 Bug Fix

Fix implementation of directives #6052
Fix issue if the lib dir is included in the sources of bsconfig.json #6055
Fix issue with string escape in pattern match #6062
Fix issue with literal comparison of string constants #6065

🚀 New Feature

Add support for toplevel await #6054

💅 Polish

Better error message for extension point #6057
Improve format check help #6056
Deprecate unsafe j`$(a)$(b)` interpolation: use string templates `${a}${b}` instead #6067

10.1.3

🚀 New Feature

Add experimental suppport for directives. An annotation such as @@directive("use client;") emits use client; verbatim before imports #5999
genType: add Core standard library support for the following builtin types: Null.t, Nullable.t, Undefined.t, Dict.t<_>, Promise.t<_>, Date.t, BigInt.t, RegExp.t, Map.t<_, _>, WeakMap.t<_, _>, Set<_>, WeakSet<_> #6024

💥 Breaking Change

genType: streamline the treatment of optionals as undefined #6024
- Represent option<t> as undefined | t instead of null | undefined | t. This is more permissive when importing functions taking optional values (allows to use option types), but stricter when e.g. exporting ReScript functions taking arguments of option type. Fallback: use Js.undefined<_> instead.
- Represent {x:option<string>} as {x:(undefined | string)} instead of {x?: string}. This is more in line with TS's behaviour. Fallback: use {x?:string}.

💅 Polish

Add the gap property to jsxDOMStyle #5956

🐛 Bug Fix

Fix issue where error messages related to non-existent props were displayed without location information rescript-lang/syntax#730
Fix issue where uncurried functions were incorrectly converting the type of a prop given as a default value to curried rescript-lang/syntax#731
Fix issue with nested async functions, where the inner function would be emitted without async #5984
Fix issue with printing async functions with locally abstract types rescript-lang/syntax#732
Fix issue with async context and locally abstract types #5985
Fix support for recursive components in JSX V4 rescript-lang/syntax#733
GenType: fix issue with V3 compatibility mode (see #5990) #5992
Fix issue with overlapping labelled argument with default value rescript-lang/syntax#734
Fix issue with using alias and default value together rescript-lang/syntax#734
Fix issue in Js.Promise2 where then and catch were returning undefined #5996
Fix issue in the compiler back-end where async functions passed to an @uncurry external would be inlined and transformed in a way that loses async #6011
Fix location issue for the treatment of async functions where hovering on the body with a type error would show 'a => promise<'a> everywhere #6014
Fix formatting of switch expressions that contain braced cases inside rescript-lang/syntax#735
Fix formatting of props spread for multiline JSX expression rescript-lang/syntax#736
Support @gentype.import as an alias to @genType.import in the compiler #6021
In GenType, check annotations also in module types to decide whether to produce the .gen.tsx file #5903
Fix issue with JSX V4 and newtype rescript-lang/syntax#737
Fix issue with JSX V4 when components are nested rescript-lang/syntax#738
Fix issue where generic compare on float values would be different from the compare for type float #6043
Improve code generated for default arguments in JSX V4 rescript-lang/syntax#739
Fix issue with JSX V4 props of the form ~p as module(...) rescript-lang/syntax#739

10.1.2

🐛 Bug Fix

Fix an issue where error messages related to duplicate props were displayed without a loc and were unclear rescript-lang/syntax#728

10.1.1

💥 Breaking Change

Parse the attributes of labelled argument to the pattern attributes of argument instead of function. rescript-lang/syntax#722
The prop names duplicated to keyword are not mangled automatically in JSX v4.
- Use @as instead

🚀 New Feature

Add support for empty inlined record literal {} for inlined records where all fields are optional #5900

🐛 Bug Fix

Prevent inlining of async functions in additional cases #5860
Fix build error where aliasing arguments to _ in the make function with JSX V4. #5881
Fix parsing of spread props as an expression in JSX V4 #5885
Fix dropping attributes from props in make function in JSX V4 #5905

10.1.0

🐛 Bug Fix

Fix issue where no error was reported when ? was used for non-optional fields. #5853
Fix issue where optional fields in inline records were not supported and would cause type errors #5827

10.1.0-rc.5

🐛 Bug Fix

Prevent inlining of async functions in last stage of the compiler when the functions are not exported (not in interface file or shadowed) #5790

10.1.0-rc.4

🚀 New Feature

Support format check with rescript format -check. #5760

🐛 Bug Fix

Fix issue where the last line of rescript format --help usage was being swallowed #5760
Specialize the printing of the rhs of a record field assignment for optional values {x: ? e} rescript-lang/syntax#714

10.1.0-rc.3

🚀 New Feature

Support the use of spread anywhere in list creation (e.g. list{...x, 1, ...y, ...z}). rescript-lang/syntax#692
Add support for the argument of @react.component to set a props type from the outside. rescript-lang/syntax#699

🐛 Bug Fix

Fix issue where the JSX key type is not an optional string rescript-lang/syntax#693
Prevent inlining of async functions #5754
Fix build error for JSX fragment without children rescript-lang/syntax#704
Fix issue where async as an id cannot be used with application and labelled arguments rescript-lang/syntax#707
Fix 5557: the exhaustive checking for char is incorrect during the unicode migration #5749
Fix 5753: the comment for unicode char is inaccurate rescript-lang/syntax#709
Treat await as almost-unary operator weaker than pipe so await foo->bar means await (foo->bar) rescript-lang/syntax#711

💅 Polish

Change payload of Pconst_char from char to int rescript-lang/syntax#709

10.1.0-rc.2

🐛 Bug Fix

Fix issue with changes not being applied with React Native's Metro bundler for files with warnings #5738
Fix emitting unary minus for floats in case of negative constants #5737
Fix issue where a spread ...x in non-last position would not be reported as syntax error rescript-lang/syntax#673
Fix issue where the formatter would delete async in a function with labelled arguments.
Fix several printing issues with async including an infinite loop rescript-lang/syntax#680
Fix issue where certain JSX expressions would be formatted differenctly in compiler 10.1.0-rc.1 rescript-lang/syntax#675
Fix issue where printing nested pipe discards await rescript-lang/syntax#687

10.1.0-rc.1

💥 Breaking Change

Deprecate DOM element attributes in JsxDOM.domProps: begin_, end_, to_
- Use begin, end, to instead.
Emit an error when a @string or @int attribute is used in a V4 component #5724

🚀 New Feature

Add extra variants for output filename suffixes in bsconfig.json: .bs.mjs and .bs.cjs are allowed #5631
Safe promises: t-first Js.Promise2 bindings, and remove warning for nested promises #5709

🐛 Bug Fix

Fix issue where uncurried async functions were emitted without async #5718
Fix location issue in error messages with JSX V4 where the multiple props types are defined rescript-lang/syntax#655
Fix location issue in make function in JSX V4 that breaks dead code elimination rescript-lang/syntax#660
Fix parsing (hence pretty printing) of expressions with underscore _ and comments.
Fix printing of comments inside JSX tag rescript-lang/syntax#664
Fix issue where formatter erases tail comments inside JSX tag rescript-lang/syntax#663
Fix issue where the JSX prop has type annotation of the first class module rescript-lang/syntax#666
Fix issue where an empty record literal {} expected to have a non-record type would type check #5729

👓 Spec Compliance

Functions with consecutive dots now print as multiple arrow functions like in JavaScript.

💅 Polish

Add loading, aria-* DOM element attributes in JsxDOM.domProps: ariaCurrent, ariaInvalid, ariaAutocomplete, etc.
Change the internal representation of props for the lowercase components to record. rescript-lang/syntax#665
Add JsxPPXReactSupport module to relocate the helper functions for JSX v4 from rescript-react

10.1.0-alpha.2

🚀 New Feature

Fix pretty printer where it would print doc comments on the same line as other attributes rescript-lang/syntax#642
Propagte "jsx" configuration to dependencies #5661
Add support for empty record literal {} for records where all fields are optional #5658
Add support for empty record type (e.g. type empty = {}) #5658

🐛 Bug Fix

Fix issue in formatting JSX spread props rescript-lang/syntax#644
Fix location issue in error messages with JSX V4 where the body of the component is an application rescript-lang/syntax#633
Fix printing of type declarations in error message where they would be considered recursive by default
Fix issue where the printer would omit attributes for -> and |> rescript-lang/syntax#629
Fix printing of optional fields in records #5654
Fix printing of comments inside empty blocks rescript-lang/syntax#647

💅 Polish

Improvements and fixes for JSX V4. See guide https://github.com/rescript-lang/syntax/blob/master/cli/JSXV4.md
Mention all missing fields in error message for records, not just one #5657

10.1.0-alpha.1

💥 Breaking Change

Pipe -> does not support a code block on the right-hand side e.g. x->{ open A; get("test") }

🚀 New Feature

Experimental support for for async/await #5537
Make promise a built-in type #5650
Initial support for JSX V4 including genType, still work in progress.
- 💥 when V4 is activated, at most one component is allowed for each module.
Add placeholder types for ES6 collections: Set, Map, WeakSet, and WeakMap #5630

🐛 Bug Fix

Fix issue with arrays and creation of recursive values #5640
Fix issue where characters such as newlines would be escaped in a template string expression #5638
Fix issue where pipe -> processing eats up attributes #5581
Fix issue where cancelling rescript build would leave the .bsb.lock file behind and block future builds

💅 Polish

Print patterns in warnings using rescript printer #5492

10.0.1

🐛 Bug Fix

Fix issue where watch mode would give an error on Windows #5621

10.0.0

Compiler

💥 Breaking Change

bsconfig.json does not support // line comments anymore.
- Example: "suffix": ".bs.js" // determine the suffix
- Fix: remove the comment and use standard json.
Changed return type of Js.String.match_ as it was wrong. #5070
- Example: any use of Js.String.match_ and Js.String2.match_
- Fix: follow the type errors
GenType is now vendored in the compiler and drops support for the Flow and untyped back-ends to focus on providing a better experience for TypeScript.
- Fix: keep on using the older version of the compiler and the separate genType package if Flow support is required. Migrate to TS if one wants to upgrade the compiler version.

🚀 New Feature

New records with optional fields e.g. type opt = {x: int, y?: string} were added as an experimental feature #5423 #5452 New Syntax
Add support for @new @variadic (see #5364)

🐛 Bug Fix

Classify bigint correctly #5351
Fixed crash in rescript build on Windows #5516
Fixed rescript init command not working #5526
Fix issue with compiler log not terminated that causes problems with editor extension not clearing issues when fixed #5545

💅 Polish

Changed Linux build to depend on GLIBC 2.28 again for compatibility with Debian 10.
Proper M1 support (CI now supports M1 native builds)

Syntax

💥 Breaking Change

@bs.send.pipe is now removed. Earlier it was deprecated.
Missing labels in function application is now an error (https://forum.rescript-lang.org/t/ann-more-strict-checks-in-missed-labels/2117).
- Example: let f = (x, ~z) => x + z; f(1, 2)
- Fix: do let f = (x, ~z) => x + z; f(1, ~z=2) instead
Externals without @val annotations do not work anymore, and externals with = "" give an error.
- Example: external setTimeout: (unit => unit, int) => float = "setTimeout" is not supported anymore.
- Fix: use @val external setTimeout: (unit => unit, int) => float = "setTimeout" instead.
- Example2: @val external setTimeout: (unit => unit, int) => float = "" is not supported anymore.
- Fix2: use @val external setTimeout: (unit => unit, int) => float = "setTimeout" instead.
Strings processed at compile-time don't need escaping anymore.
- Example: let blockCommentsRe = %re("/\\/\\*([^*]|[\\r\\n]|(\\*+([^*/]|[\\r\\n])))*\\*+\\//g").
- Fix: use let blockCommentsRe = %re("/\/\*([^*]|[\r\n]|(\*+([^*/]|[\r\n])))*\*+\//g") instead.
Remove parsing of "import" and "export" which was never officially supported rescript-lang/syntax#597 rescript-lang/syntax#599
- Example: export type t = int
- Fix: @genType type t = int
- Example2: import realValue: complexNumber => float from "./MyMath"
- Fix2: @genType.import("./MyMath") external realValue: complexNumber => float = "realValue"

🚀 New Feature

Unicode is now supported in regular strings and chars (when the symbol fits). This is now going to work: let str = "Σ". And, you'll be able to pattern match on unicode chars: switch c { | 'Σ' => "what a fine unicode char" | _ => "unicode is fun" }
Doc comments /** ... */ are now supported. Inernally, they are attributes, so are only valid at positions where @foo is allowed, or a syntax error is given. Similarly for module-level /*** comments */ that can go where @@attributes go.

🐛 Bug Fix

Fix printing for inline nullary functor types #477
Fix stripping of quotes for empty poly variants #474
Implement syntax for arity zero vs arity one in uncurried application in #139
Fix parsing of first class module exprs as part of binary/ternary expr in #256
Fix formatter hanging on deeply nested function calls #261

Libraries

💥 Breaking Change

"Attributes not allowed here". If you see this error chances are you're using a ppx that needs updating to a new version. See an exampe of how to update a ppx
- Example: for rescript-relay 0.23.0 is not supported.
- Fix: use rescript-relay@beta or the new version when released.
Removed printing modules (Printf, Format etc) and related functions. Details of files added/removed: https://github.com/rescript-lang/rescript-compiler/commit/0fd8bb0e77c4b0e96a9647ac8af614305057003f.

🐛 Bug Fix

Fix library issue with missing bytes_to_string #5573 #5589

💅 Polish

Several Belt / Js libraries are now converted to ReScript syntax, with corresponding comments in Markdown format suitable for hovering. See #5361.

Playground

🏠 Internal

Added jsoo_playground_main.ml as the rescript-lang.org playground bundle entrypoint

💥 Breaking Change

Removed Reason syntax support for the playground experience. See #5375

You can find more old changelog from docs/changelog

Files

CHANGELOG.md

Latest commit

History

CHANGELOG.md

File metadata and controls

Changelog

12.0.0-alpha.7 (Unreleased)

🏠 Internal

💅 Polish

12.0.0-alpha.6

🚀 New Feature

🐛 Bug fix

🏠 Internal

12.0.0-alpha.5

🚀 New Feature

🐛 Bug fix

💅 Polish

🏠 Internal

12.0.0-alpha.4

💥 Breaking Change

🚀 New Feature

🐛 Bug fix

💅 Polish

🏠 Internal

12.0.0-alpha.3

🐛 Bug fix

12.0.0-alpha.2

🚀 New Feature

🐛 Bug Fix

🏠 Internal

💅 Polish

12.0.0-alpha.1

🚀 New Feature

💥 Breaking Change

🐛 Bug Fix

🏠 Internal

💅 Polish

11.1.3

🐛 Bug Fix

11.1.3-rc.1

🐛 Bug Fix

11.1.2

🐛 Bug Fix

11.1.2-rc.1

🚀 New Feature

🐛 Bug Fix

11.1.1

🐛 Bug Fix

11.1.0

🐛 Bug Fix

11.1.0-rc.8

🚀 New Feature

🐛 Bug Fix

💅 Polish

11.1.0-rc.7

🐛 Bug Fix

11.1.0-rc.6

🚀 New Feature

🐛 Bug Fix

11.1.0-rc.5

🐛 Bug Fix

11.1.0-rc.4

🐛 Bug Fix

:nail-care: Polish

11.1.0-rc.3

💅 Polish

🐛 Bug Fix

11.1.0-rc.2

🚀 New Feature

🐛 Bug Fix

🏠 Internal

11.1.0-rc.1

🚀 New Feature

🐛 Bug Fix

11.0.1

🐛 Bug Fix

💅 Polish

11.0.0

11.0.0-rc.9