rollup.config.js

import commonjs from 'rollup-plugin-commonjs'
import babel from 'rollup-plugin-babel'
import resolve from 'rollup-plugin-node-resolve'
import peerDepsExternal from 'rollup-plugin-peer-deps-external'
import serve from 'rollup-plugin-serve'
import replace from '@rollup/plugin-replace'

import pkg from './package.json'

const isDev = !!process.env.ROLLUP_WATCH

const commonJsConfig = {
  include: 'node_modules/**',
  namedExports: {
    react: [
      'createContext',
      'useContext',
      'useEffect',
      'useMemo',
      'useState'
    ]
  }
}

const libConfig = {
  input: 'src/index.js',
  external: ['react', 'prop-types'],
  output: [
    {
      file: pkg.main,
      format: 'cjs'
    },
    {
      file: pkg.module,
      format: 'esm'
    }
  ],
  plugins: [
    commonjs(commonJsConfig),
    peerDepsExternal(),
    resolve(),
    babel({
      exclude: 'node_modules/**'
    })
  ]
}

const buildConfig = [libConfig]

if (isDev) {
  buildConfig.push({
    input: 'example/index.js',
    output: {
      file: 'dist/demo.js',
      format: 'cjs'
    },
    plugins: [
      commonjs(commonJsConfig),
      resolve(),
      babel({
        exclude: 'node_modules/**'
      }),
      replace({
        'process.env.NODE_ENV': JSON.stringify('production')
      }),
      serve({
        contentBase: ['dist', 'example']
      })
    ]
  })
}

export default buildConfig