rollup.config.js

const definition = require("./package.json");
const dependencies = Object.keys(definition.dependencies || {});

import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';

export default [
  // browser-friendly UMD build
  {
    input: 'index.js',
    output: {
      extend: true,
      name: "uia",
      file: definition.browser,
      format: 'umd'
    },
    plugins: [
      resolve(), // so Rollup can find `ms`
      commonjs() // so Rollup can convert `ms` to an ES module
    ],
  },

  // CommonJS (for Node) and ES module (for bundlers) build.
  // (We could have three entries in the configuration array
  // instead of two, but it's quicker to generate multiple
  // builds from a single configuration where possible, using
  // an array for the `output` option, where we can specify
  // `file` and `format` for each target)
  {
    input: 'index.js',
    external: dependencies,
    output: [{
        file: definition.main,
        format: 'cjs'
      },
      {
        file: definition.module,
        format: 'es'
      }
    ]
  }
];