rescript-remix

Bindings and helpers for Remix.

Installation

If you don't already have have a Remix project the easiest way to get started quickly is to use the template found here. Otherwise, continue reading this guide if you prefer manual setup or want to understand how the template works.

Setup and install

You should already have a Remix project setup. You can create one by following the Remix docs.

Once you have a Remix project, install the necessary dependencies:

npm install rescript rescript-remix patch-package @rescript/react rescript-webapi

🙋 What is each package for?

• rescript - The ReScript compiler and standard library.
• rescript-remix - This package. Includes Remix bindings and helpers.
• patch-package - A tool to patch Remix itself to workaround lack of ESM support (more about this later).
• @rescript/react - React bindings for ReScript.
• rescript-webapi - ReScript bindings for Web Platform APIs eg. fetch and Request

Add bsconfig.json

Create a bsconfig.json file at the root of your repo. Copy the contents from the template in and change the "name" to your project name. This can be anything you want but it's recommended to match the one you gave in package.json for consistency.

🙋 Why do we need all of these settings?

You can read about what all the options are for in the ReScript docs. The recommended settings are setup in such a way to be most convenient to ReScript and Remix developers alike while supporting the file-system-based routing of Remix.

Patch the ReScript compiler

Copy the patch from the template into your project, making sure to place it in the patches/ directory and matching the file name exactly. The patch in the template works on a specific version of @remix-run/dev, you may need to ensure that your version of @remix-run/dev matches the one in the template.

Next, modify (or add) the postinstall script in package.json to include the patch-package script.

...
   "scripts": {
     "build": "rescript build && remix build",
     "dev:remix": "remix dev",
     "dev:rescript": "rescript build -w",
-    "postinstall": "remix setup node",
+    "postinstall": "patch-package && remix setup node",
     "start": "remix-serve build"
   },
...

Run npm i to apply the patch.

🙋 What does the patch do?

It allows Remix to transpile ES modules (export/import syntax) inside of node_modules. This is important because our ReScript configuration tells the compiler to transpile to ESM, and this includes ReScript dependencies in node_modules eg. this package and the ReScript standard library.

Enable transpilation of ESM modules

Add "rescript" to the transpileModules option in remix.config.js. This ensures that our patch installed above will transpile the ReScript standard library.

 /**
  * @type {import('@remix-run/dev/config').AppConfig}
  */
 module.exports = {
   appDirectory: "app",
   assetsBuildDirectory: "public/build",
   publicPath: "/build/",
   serverBuildDirectory: "build",
   devServerPort: 8002,
   ignoredRouteFiles: [".*", "*.res"],
+  transpileModules: ["rescript"],
 };

You'll need to add more packages to this array whenever you receive a Remix error message that says it failed to compile ESM syntax. This is often the case when you install a new ReScript dependency.

Enable convention based routing for ReScript modules

Add a routes option to remix.config.js and inside call the registerRoutes function exported by rescript-remix/registerRoutes:

+ const { registerRoutes } = require('rescript-remix/registerRoutes');

 /**
  * @type {import('@remix-run/dev/config').AppConfig}
  */
 module.exports = {
   appDirectory: "app",
   assetsBuildDirectory: "public/build",
   publicPath: "/build/",
   serverBuildDirectory: "build",
   devServerPort: 8002,
   ignoredRouteFiles: [".*", "*.res"],
   transpileModules: ["rescript"],
+  routes(defineRoutes) {
+    return defineRoutes(route => {
+      registerRoutes(route);
+    });
+  }
 };

This allows you to use all of the convention-based routing of Remix with ReScript modules by placing them inside the app/res-routes director. See the usage section for more details.

(optional) Git ignore compiled JS

JS is outputted alongside ReScript modules to enable convention based routing. You can opt to not commit these build artifacts by adding the following lines to .gitignore:

/app/**/*.jsx
/app/**/*.js

This step is optional as it's personal preference. Some people prefer to check in the artifacts generated by ReScript to enable teammates that aren't familiar with the language to make quick changes, or to ensure the output from the compiler is as expected.

Adopting into an existing Remix app

todo

Usage

todo

Convention based routing

todo