Converted @rollup/html to a standalone package (out of the original monorepo) and made it ESM-native

rollup.config.mjs

@@ -0,0 +1,80 @@
+import {readFileSync} from "node:fs";
+import {builtinModules} from "node:module";
+import {resolve, join} from "node:path";
+
+import nodeResolve from "@rollup/plugin-node-resolve";
+import babelPlugin from "@rollup/plugin-babel";
+import deletePlugin from "rollup-plugin-delete";
+
+
+/**
+ * Create a base rollup config
+ * @param {Record<string,any>} pkg Imported package.json
+ * @param {string[]} external Imported package.json
+ * @returns {import('rollup').RollupOptions}
+ */
+export function createConfig({ pkg, external = [] }) {
+  const commonOpts = {
+    extensions: ['.js', '.mjs', '.jsx', '.ts', '.tsx'],
+    exclude: 'node_modules/**',
+  };
+
+  return {
+    input: 'src/index.ts',
+    external: Object.keys(pkg.dependencies || {})
+        .concat(Object.keys(pkg.peerDependencies || {}))
+        .concat(builtinModules)
+        .concat(external),
+    onwarn: (warning) => {
+      throw Object.assign(new Error(), warning);
+    },
+    strictDeprecations: true,
+    output: [
+      {
+        format: 'cjs',
+        file: pkg.main,
+        exports: 'named',
+        footer: 'module.exports = Object.assign(exports.default, exports);',
+        sourcemap: true
+      },
+      {
+        format: 'es',
+        file: pkg.module,
+        plugins: [emitModulePackageFile()],
+        sourcemap: true
+      }
+    ],
+    plugins: [
+      deletePlugin({
+        targets: join('./dist','*'),
+        runOnce: true,
+      }),
+      nodeResolve({
+        ...commonOpts,
+        browser: true,
+      }),
+      babelPlugin({
+        ...commonOpts,
+        babelHelpers: "bundled",
+      }),
+      // typescript({ sourceMap: true })]
+    ]
+  };
+}
+
+export function emitModulePackageFile() {
+  return {
+    name: 'emit-module-package-file',
+    generateBundle() {
+      this.emitFile({
+        type: 'asset',
+        fileName: 'package.json',
+        source: `{"type":"module"}`
+      });
+    }
+  };
+}
+
+export default createConfig({
+  pkg: JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf8'))
+});