text: const replace = require('rollup-plugin-replace')
  const resolve = require('rollup-plugin-node-resolve')
  const babel = require('rollup-plugin-babel')
  const uglify = require('rollup-plugin-uglify')
  const filesize = require('rollup-plugin-filesize')
  const version = process.env.VERSION || require('./package.json').version
  
  module.exports = {
    entry: 'src/index.js',
    dest: 'dist/build.js',
    format: 'umd',
    moduleName: 'Ency',
    external (id) { // modules that should remain external 
      if (/babel-runtime\/.*/i.test(id)) return true
    },
    plugins: [
      replace({ __VERSION__: version }),
      babel({
        exclude: 'node_modules/**', // only transpile our source code
        runtimeHelpers: true
      }),
      resolve(),
      uglify(),
      filesize()
    ],
    banner:
      `/**
        * ency v${version}
        * (c) ${new Date().getFullYear()} Alid Castano
        * @license MIT
        */`
  }
  