rollup.config.js

import babel from 'rollup-plugin-babel';
import replace from 'rollup-plugin-replace';
import { sizeSnapshot } from 'rollup-plugin-size-snapshot';
import { terser } from 'rollup-plugin-terser';

import pkg from './package.json';

const input = 'src/react-scroll-up-button.js';

const babelOptionsCJS = {
  exclude: /node_modules/,
};

const babelOptionsESM = {
  exclude: /node_modules/,
  runtimeHelpers: true,
  plugins: [['@babel/transform-runtime', { useESModules: true }]],
};

const external = id => !id.startsWith('.') && !id.startsWith('/');

export default [
  {
    input,
    output: { file: `dist/cjs/${pkg.name}.js`, format: 'cjs' },
    external,
    plugins: [
      babel(babelOptionsCJS),
      replace({ 'process.env.NODE_ENV': JSON.stringify('development') }),
    ],
  },

  {
    input,
    output: { file: `dist/cjs/${pkg.name}.min.js`, format: 'cjs' },
    external,
    plugins: [
      babel(babelOptionsCJS),
      replace({ 'process.env.NODE_ENV': JSON.stringify('production') }),
      terser(),
    ],
  },

  {
    input,
    output: { file: `dist/esm/${pkg.name}.js`, format: 'esm' },
    external,
    plugins: [babel(babelOptionsESM), sizeSnapshot()],
  },
];