Jan 11, 2024

ReScript 11.0

The ReScript developer experience now goes up to eleven!

ReScript Team
Core Development

Almost a year after the last release, ReScript is available in version 11! It marks the second major community-driven release and we are very thankful that there are so many willing contributors who invested their spare time into improving the compiler and its ecosystem.

To upgrade your project or to find out if there are any breaking changes that affect you, please follow the migration guide.

The complete list of changes can be found here. Let's have a look at the most notable improvements.

Compiler

Use your favorite package manager to install the new compiler release, e.g:

SH
npm install rescript@11

As this release is packed, please refer to the following blogposts for a detailed breakdown of each of the main new features:

Furthermore, there are a lot of smaller improvements of which we want to state only a few here.

More types eligible for type coercion

The :> (type coercion) operator now supports a few more datatypes, check out its Syntax Lookup page.

Build System

The watcher can now be called with just rescript -w. Also rescript build will always build with dependencies by default so the argument -with-deps is not needed anymore.

rescript.json

The compiler config file has been renamed to rescript.json. Since the rebrand from BuckleScript to ReScript, the bs- names make no sense anymore. Later on, we will also rename some of the config attributes, like bs-dependencies.

Relaxed Suffix Rules

You can now freely choose the suffix of the generated JS files. For instance instead of .bs.js you can now use .res.js.

Opening files from current project globally

It's now possible to have a module opened by default that is just part of the current project. Previously, this only worked with dependencies or namespaced projects. For example, a file with the path src/Utils.res can be added to bsc-flags like so:

JSON
{
  "bsc-flags": ["-open Utils"]
}

Ecosystem

Rescript Core

ReScript Core is ReScript's new standard library. It replaces the complete Js module as well as some of the more frequently used modules from Belt and is recommended to use with uncurried mode.

The latest docs on rescript-lang.org already use it for the examples, but please bear in mind that the API docs are not updated to it yet. This will happen soon though.

Create-ReScript-App

Previously, the ReScript binary was able to initialize new projects itself. But it was required to have a global npm install to use it. This functionality has been removed.

Going forward, create-rescript-app is the new recommended way to setup a new project. It can even be used to quickly add ReScript to an existing project. Have a look at the updated installation instructions for how to use it.

ReScript-React v0.12

In tandem with the new ReScript release, a new version of ReScript-React is released as well. It brings support for dynamically loading React components via React.lazy, and more. Check out the corresponding docs.

ReScript Tools / Documentation Extraction

There is a new experimental tool available that is a building block for documentation generation from ReScript files. It can be installed and used as follows:

SH
npm install --save-dev @rescript/tools
npx rescript-tools doc src/MyFile.res > doc.json

The tool generates a JSON structure with all the information you need to generate documentation automatically for your ReScript code. It also comes with ReScript bindings for that JSON. Shortly we'll also have automatic markdown generation, and we're planning a static site generator as well, so getting a nice looking and useful documentation site for your ReScript code is just a command away.

LSP

Our LSP powers our editor tooling. Historically, it has lived within the VSCode extension. This has been a problem for people who do not use VSCode. So, we've made sure that each new LSP version is published standalone to NPM.

This makes using an up-to-date version of the LSP in other editors than VSCode much easier. You can install and use it like so:

SH
npm install -g @rescript/language-server
npx rescript-language-server --stdio

What's next

As we now finish up the work on v11, we're looking forward to working on the next ReScript version. Here are some of the features we're planning to focus on in upcoming versions:

Acknowledgements

We want to thank everyone from the community who volunteered their precious time to support this project with contributions of any kind, from documentation, to PRs, to discussions in the forum.

That's it

We hope you enjoy the newest improvements as much as we do.

In case of issues / problems, make sure to report bugs to one of the following repositories:

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