ReScript 11.1

A couple of weeks ago, the ReScript team released ReScript 11.0, which laid ground work for a lot of possible improvements to make it easier to interact with the JavaScript ecosystem.

This next minor has some wonderful additions to the ReScript toolbelt for you today.

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

SH
npm install rescript@11.1

Find a list of all the new features below:

JSX for more than React

Historically, ReScript has focused mainly on React for its frontend support. This has led to ReScript having a great JSX transform built into the language itself. However, that JSX transform has been quite difficult to use with anything but React.

With v11.1, that changes! The JSX transform can now be configured to work with any framework. First class React support is of course still the same, and remains a priority. This makes it possible to integrate any other framework's JSX idiomatically in ReScript. And, all the tooling like autocompletion of prop names and types just works.

Many popular frameworks like Vue and Preact use JSX. But, JSX is also becoming more and more ubiquitous, and these days JSX can also be used for everything from building CLI apps to responsive e-mail templating. We're happy that ReScript users will now be able to leverage all of these innovations in a more idiomatic way than before.

Here's an example of what a Preact integration could look like:

RESCRIPT
// Greet.res

// @jsx.component works the same as @react.component does in React
@jsx.component
let make = (~name) => {
  <div>
    {Preact.string("Hello " ++ name)}
  </div>
}

Read more in the new documentation on the generic JSX transform.

Tagged template literals

This release comes with support for tagged templates.

A tag function in JavaScript is a function that expects an array of strings and variadic parameters as input. Now it's possibe to bind to such functions with the new @taggedTemplate decorator:

// see https://bun.sh/docs/runtime/shell
type result = {exitCode: int}
@module("bun") @taggedTemplate
external sh: (array<string>, array<string>) => promise<result> = "$"

let filename = "index.res"
let result = await sh`ls ${filename}`

Of course you can also create your own tag functions in ReScript now as well, it is just a function with the following signature.

RESCRIPT
let myTagFunction : (array<string>, array<'param>) => 'output

Refer to the docs to find a detailed example.

Import attributes

Import attributes is a JS feature that is currently in standardization, but is already implemented by many JS tools. Now, ReScript supports it too, as long as the compiler is configured to output ES6.

@module({from: "./myJson.json", with: {type_: "json", \"some-identifier": "yep"}})
external myJson: Js.Json.t = "default"
Console.log(myJson)

@module({from: "./myCss.css", with: {type_: "css", \"some-identifier": "yep"}})
external buttonCss: string = "button"
Console.log(buttonCss)

Array spread syntax

The spread syntax, which was already supported for records and lists for a long time, now also supports arrays!

RESCRIPT
let animals = ["🐶", "🐱", "🐷"]
let moreAnimals = [...animals, "🐔", "🐴", "🐮"]

Hyphens in JSX tag names

We lifted restrictions on JSX tag names. This means you no longer need to escape tag names that contain hyphens:

Previously:

RESCRIPT
let x = <\"custom-tag" />
let y = <Foo.\"custom-tag" />

Now:

RESCRIPT
let x = <custom-tag />
let y = <Foo.custom-tag />

Acknowledgements

Once again 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. But especially we want to thank the following people, who helped landing this release:

@cknitt, @cometkim, @cristianoc, @diogomqbm, @kevinbarabash, @shulhi, @tsnobip, @zth.

That's it

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

If you find any problems with this new release, make sure to report them here:

• rescript-lang/rescript-compiler