11.0.0

ReScript's second major community-driven release is out and comes packed with new features and improvements! 🎉

🚀 Highlights

• Customizable Variants
• Enhanced Ergonomics for Record Types
• First-class Dynamic Import Support
• Uncurried Mode
• New Standard Library: ReScript Core

📋 More Information

• ReScript 11 Release Blog Post
• Changelog

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