rollup.config.js

import { builtinModules } from 'module';
import { readFileSync } from 'fs';
// eslint-disable-next-line import/no-extraneous-dependencies
import typescript from '@rollup/plugin-typescript';

/**
 * 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 emitModulePackageFile() {
  return {
    name: 'emit-module-package-file',
    generateBundle() {
      this.emitFile({
        type: 'asset',
        fileName: 'package.json',
        source: `{"type":"module"}`
      });
    }
  };
}

const pkg = JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf8'));
export default {
      input: 'src/index.ts',
      external: Object.keys(pkg.dependencies || {})
        .concat(Object.keys(pkg.peerDependencies || {}))
        .concat(builtinModules),
      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: false
        },
        {
          format: 'es',
          file: pkg.module,
          plugins: [emitModulePackageFile()],
          sourcemap: false
        }
      ],
      plugins: [typescript({ sourceMap: false })]
    };