rollup.config.js

import babel from 'rollup-plugin-babel'
import commonjs from 'rollup-plugin-commonjs'
import pkg from './package.json'
import resolve from 'rollup-plugin-node-resolve'
import uglify from 'rollup-plugin-uglify'

export default [
  // browser-friendly UMD build
  {
    input: 'js/index.js',
    output: {
      name: 'custom-tooltips',
      file: pkg.browser,
      format: 'umd',
      sourcemap: true
    },
    plugins: [
      resolve(), // so Rollup can find `ms`
      commonjs(), // so Rollup can convert `ms` to an ES module
      babel({
        exclude: 'node_modules/**' // only transpile our source code
      })
    ]
  },
  {
    input: 'js/index.js',
    output: {
      name: 'custom-tooltips',
      file: pkg.browserMin,
      format: 'umd',
      sourcemap: true
    },
    plugins: [
      resolve(), // so Rollup can find `ms`
      commonjs(), // so Rollup can convert `ms` to an ES module
      babel({
        exclude: 'node_modules/**' // only transpile our source code
      }),
      uglify()
    ]
  },
  // 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: 'js/index.js',
    external: ['ms'],
    output: [
      {
        file: pkg.main,
        format: 'cjs',
        sourcemap: true
      },
      {
        file: pkg.module,
        format: 'es',
        sourcemap: true
      }
    ],
    plugins: [
      resolve(),
      babel({
        exclude: 'node_modules/**' // only transpile our source code
      })
    ]
  }
]