rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import uglify from 'rollup-plugin-uglify';
import json from 'rollup-plugin-json';
import babel from 'rollup-plugin-babel';
import eslint from 'rollup-plugin-eslint';
import eslintConfig from 'eslint-config-airbnb';


// `npm run build` -> `production` is true
// `npm run dev` -> `production` is false
const production = !process.env.ROLLUP_WATCH;

export default {
  input: 'src/index.js',
  output: {
    file: 'public/index.js',
    sourcemap: true,
    format: 'cjs'
  },
  plugins: [
    eslint(eslintConfig),
    babel({
      exclude: 'node_modules/**'
    }),
    resolve(), // tells Rollup how to find date-fns in node_modules
    commonjs({
      exclude: 'node_modules/**'
    }), // converts date-fns to ES modules
    production && uglify(), // minify, but only in production
    json()
  ]
};