rollup.config.js

import path from 'path';
import babel from '@rollup/plugin-babel';
import resolve from '@rollup/plugin-node-resolve';
import json from '@rollup/plugin-json';
import { terser } from 'rollup-plugin-terser';
import filesize from 'rollup-plugin-filesize';

const root = process.platform === 'win32' ? path.resolve('/') : '/';
const external = id => !id.startsWith('.') && !id.startsWith(root);
const extensions = ['.js', '.jsx', '.ts', '.tsx', '.json'];

const getBabelOptions = ({ useESModules }, targets) => ({
  babelrc: false,
  extensions,
  exclude: '**/node_modules/**',
  babelHelpers: 'runtime',
  presets: [['@babel/preset-env', { loose: true, modules: false, targets }], '@babel/preset-react', '@babel/preset-typescript'],
  plugins: [['@babel/transform-runtime', { regenerator: false, useESModules }]],
});

export default [
  {
    input: `./src/index.ts`,
    output: { file: `dist/index.js`, format: 'esm' },
    external,
    plugins: [
      json(),
      babel(getBabelOptions({ useESModules: true }, '>1%, not dead, not ie 11, not op_mini all')),
      resolve({ extensions }),
      terser(),
      filesize(),
    ],
  },
  {
    input: `./src/index.ts`,
    output: { file: `dist/index.cjs`, format: 'cjs' },
    external,
    plugins: [json(), babel(getBabelOptions({ useESModules: false })), resolve({ extensions }), terser(), filesize()],
  },
];