vite-plugin-melange

A Vite plugin for Melange.

Features

• Compile Melange source files as part of the build
• Show errors on the commandline and in the browser overlay
• HMR (hot module replacement) with Melange source filenames as module names

Usage

npm install --save-dev vite-plugin-melange

vite.config.js:

import { defineConfig } from "vite";
import melangePlugin from "vite-plugin-melange";

export default defineConfig({
  plugins: [
    melangePlugin({
      buildCommand: "opam exec -- dune build",
      watchCommand: "opam exec -- dune build --watch",
    }),
  ],
  server: {
    watch: {
      awaitWriteFinish: {
        stabilityThreshold: 500,
        pollInterval: 20,
      },
    },
  },
});

The watch part is configuring chokidar so that the many writes Melange does to its log file appear as a single change (we use the log file to determine when compilation has finished). You may have to tweak it, depending on your project and hardware.

Options

• buildCommand: (required) Dune build command. For instance: opam exec -- dune build
• watchCommand: (required) Dune watch command. For instance: opam exec -- dune build --watch
• buildContext: (default: "default") Dune build context. The default corresponds to Dune's default
• emitDir: (default: "") directory where the melange.emit stanza is located. It defaults to empty string, which means the project's root folder, as it's the recommended location
• buildTarget: (default: "output") target field of the melange.emit stanza. It defines the directory where the JavaScript artifacts will be placed

Build

npm install
npm run build