rollup.bundles.js

const commonjs = require('@rollup/plugin-commonjs');
const nodeResolve = require('rollup-plugin-node-resolve');
const babel = require('rollup-plugin-babel');
const progress = require('rollup-plugin-progress');
const filesize = require('rollup-plugin-filesize');
const { terser } = require('rollup-plugin-terser');
const pkg = require('./package.json');

const outputPath = 'lib';
const filename = pkg.name;

const banner = `/*
${pkg.name} @ ${pkg.version}
License: ${pkg.license}
Built: ${new Date().toISOString()}
*/`;

const config = ({ minify = false } = {}) => {
  const input = 'src/index.js';
  const watch = {
    include: 'src/**',
  };

  const babelConfig = {
    exclude: 'node_modules/**', // only transpile our source code
    presets: [
      [
        '@babel/preset-env',
        {
          modules: false,
          useBuiltIns: 'entry',
          corejs: '2.6.12',
          targets: {
            browsers: [
              'last 2 chrome versions',
              'last 2 firefox versions',
              'last 1 edge version',
              'last 1 safari version',
            ],
            node: '12.0',
          },
        },
      ],
    ],
  };

  const plugins = [
    progress(),
    commonjs(),
    nodeResolve({
      module: true,
      main: true,
      jsnext: false,
      browser: false,
      preferBuiltins: true,
    }),
    babel(babelConfig),
    filesize(),
  ];

  if (minify) {
    plugins.push(terser());
  }

  return {
    input,
    plugins,
    watch,
  };
};

exports.main = {
  ...config(),
  output: [
    {
      file: `${outputPath}/${filename}.mjs`,
      format: 'es',
      name: pkg.name,
      banner,
    },
    {
      file: `${outputPath}/${filename}.js`,
      format: 'umd',
      name: pkg.name,
      sourcemap: true,
      banner,
    },
  ],
};

exports.min = {
  ...config({ minify: true }),
  output: {
    file: `${outputPath}/${filename}.min.js`,
    format: 'umd',
    name: pkg.name,
    sourcemap: true,
  },
};