rollup.config.js

import path from 'path'
import resolve from 'rollup-plugin-node-resolve'
import { terser } from 'rollup-plugin-terser'
import pkg from './package.json'

const input = './compiled/index.js'

const external = (id) => !id.startsWith('.') && !path.isAbsolute(id)

const buildCjs = () => ({
  input,
  external,
  output: {
    file: pkg.main,
    format: 'cjs',
    sourcemap: true,
  },
  plugins: [
    resolve(),
    terser({
      sourcemap: true,
      output: { comments: false },
      warnings: true,
      ecma: 5,
      // Compress and/or mangle variables in top level scope.
      // @see https://github.com/terser-js/terser
      toplevel: true,
    }),
  ],
})

export default [
  buildCjs(),
  {
    input,
    external,
    output: {
      file: pkg.module,
      format: 'esm',
      sourcemap: true,
    },
    plugins: [resolve()],
  },
]