title | description | canonical |
---|---|---|
Installation |
ReScript installation and setup instructions |
/docs/manual/v11.0.0/installation |
With the instructions below, our new standard library ReScript Core will be included by default. (In ReScript 11, it comes as a separate npm package @rescript/core
. In future versions, it will be included in the rescript
npm package itself.)
- Node.js version >= 14
- One of the following package managers:
The fastest and easiest way to spin up a new ReScript project is with the create-rescript-app project generator. You can start it with any of the aforementioned package managers or npx
.
<CodeTab labels={["npm", "npx", "yarn", "pnpm", "bun"]}>
npm create rescript-app@latest
npx create-rescript-app
yarn create rescript-app
pnpm create rescript-app
bun create rescript-app
- Follow the steps of the setup.
- Trigger a ReScript build:
npm run res:build
- If you selected the "basic" template, simply run it with:
node src/Demo.res.js
That compiles your ReScript into JavaScript, then uses Node.js to run said JavaScript.
When taking your first steps with ReScript, we recommend you use our unique workflow of keeping a tab open for the generated JS file (.res.js
/.res.mjs
), so that you can learn how ReScript transforms into JavaScript. Not many languages output clean JavaScript code you can inspect and learn from! With our VS Code extension, use the command "ReScript: Open the compiled JS file for this implementation file" to open the generated JS file for the currently active ReScript source file.
During development, instead of running npm run res:build
each time to compile, use npm run res:dev
to start a watcher that recompiles automatically after file changes.
If you already have a JavaScript project into which you'd like to add ReScript you can do that in the following ways:
In the root directory of your project, execute: <CodeTab labels={["npm", "npx", "yarn", "pnpm", "bun"]}>
npm create rescript-app@latest
npx create-rescript-app
yarn create rescript-app
pnpm create rescript-app
bun create rescript-app
create-rescript-app
will tell you that a package.json
file has been detected and ask you if it should install ReScript into your project. Just follow the steps accordingly.
-
Install ReScript locally: <CodeTab labels={["npm", "yarn", "pnpm", "bun"]}>
npm install rescript @rescript/core
yarn add rescript @rescript/core
pnpm install rescript @rescript/core
bun install rescript @rescript/core
-
Create a ReScript build configuration file (called
rescript.json
) at the root:{ "name": "your-project-name", "sources": [ { "dir": "src", // update this to wherever you're putting ReScript files "subdirs": true } ], "package-specs": [ { "module": "esmodule", "in-source": true } ], "suffix": ".res.js", "bs-dependencies": [ "@rescript/core" ], "bsc-flags": [ "-open RescriptCore" ] }
See Build Configuration for more details on
rescript.json
. -
Add convenience
npm
scripts topackage.json
:"scripts": { "res:build": "rescript", "res:dev": "rescript -w" }
Since ReScript compiles to clean readable JS files, the rest of your existing toolchain (e.g. Babel and Webpack) should just work!
Helpful guides:
To start a rescript-react app, or to integrate ReScript into an existing ReactJS app, follow the instructions here.