rollup.config.js

import babel from "@rollup/plugin-babel";
import commonjs from "@rollup/plugin-commonjs";
import nodeResolve from "@rollup/plugin-node-resolve";
import replace from "@rollup/plugin-replace";
import metablock from "rollup-plugin-userscript-metablock";

const fs = require("fs");
const pkg = require("./package.json");

fs.mkdir("dist/", { recursive: true }, () => null);

export default {
  input: "src/index.js",
  output: {
    file: "dist/bundle.user.js",
    format: "iife",
    name: "rollupUserScript",
    banner: () =>
      "\n/*\n" +
      fs.readFileSync("./LICENSE", "utf8") +
      "*/\n\n/* globals React, ReactDOM */",
    sourcemap: true,
    globals: {
      react: "React",
      "react-dom": "ReactDOM",
    },
  },
  plugins: [
    replace({
      "process.env.NODE_ENV": JSON.stringify("production"),
      ENVIRONMENT: JSON.stringify("production"),
      preventAssignment: true,
    }),
    nodeResolve({ extensions: [".js", ".ts", ".tsx"] }),
    commonjs({
      include: ["node_modules/**"],
      exclude: ["node_modules/process-es6/**"],
    }),
    babel({ babelHelpers: "bundled" }),
    metablock({
      file: "./meta.json",
      override: {
        name: pkg.name,
        version: pkg.version,
        description: pkg.description,
        author: pkg.author,
        license: pkg.license,
      },
    }),
  ],
  external: (id) => /^react(-dom)?$/.test(id),
};