rollup.config.mjs

import * as fs from 'fs'
import terser from '@rollup/plugin-terser'
import filesize from 'rollup-plugin-filesize'
import license from 'rollup-plugin-license'

const loadJSON = (path) =>
  JSON.parse(fs.readFileSync(new URL(path, import.meta.url)))

const pkg = loadJSON('./package.json')

const licenseBanner = license({
  banner: {
    content: '/*! <%= pkg.name %> v<%= pkg.version %> | <%= pkg.license %> */',
    commentStyle: 'none'
  }
})

export default [
  {
    input: 'src/api.mjs',
    output: [
      // config for <script type="module">
      {
        file: pkg.module,
        format: 'esm'
      },
      // config for <script nomodule>
      {
        file: pkg.browser,
        format: 'umd',
        name: 'Cookies',
        noConflict: true,
        banner: ';'
      }
    ],
    plugins: [licenseBanner]
  },
  {
    input: 'src/api.mjs',
    output: [
      // config for <script type="module">
      {
        file: pkg.module.replace('.mjs', '.min.mjs'),
        format: 'esm'
      },
      // config for <script nomodule>
      {
        file: pkg.browser.replace('.js', '.min.js'),
        format: 'umd',
        name: 'Cookies',
        noConflict: true
      }
    ],
    plugins: [
      terser(),
      licenseBanner, // must be applied after terser, otherwise it's being stripped away...
      filesize()
    ]
  }
]