rollup.config.js

import pkg from './package.json'
// import commonjs from 'rollup-plugin-commonjs' // Convert CommonJS modules to ES6
import vue from 'rollup-plugin-vue' // Handle .vue SFC files
import buble from '@rollup/plugin-buble' // Transpile/polyfill with reasonable browser support
import alias from '@rollup/plugin-alias'
import resolve from 'rollup-plugin-node-resolve'
import replace from '@rollup/plugin-replace'
import { uglify } from 'rollup-plugin-uglify'
// import css from 'rollup-plugin-css-only'

const path = require('path')

const version = pkg.version
const banner = `
/*!
 * TreeVue v${version}
 * (c) ${new Date().getFullYear()} Anatoliy Ivanov
 * Released under the MIT License.
 */
`
console.log('__dirname', __dirname)

const plugins = [
  replace({
    'process.env.NODE_ENV': JSON.stringify('production')
  }),
  alias({
    resolve: ['.vue', '.js'],
    entries: {
      '@': path.resolve(__dirname, 'src')
    }
  }),
  resolve(),
  // commonjs(),
  // css(),
  vue({
    css: true // Dynamically inject css as a <style> tag
  }),
  buble({ transforms: { dangerousForOf: true } }) // Transpile to ES5
]

export default [
  // ESM build to be used with webpack/rollup.
  {
    input: 'src/index.js', // Path relative to package.json
    output: {
      format: 'esm',
      file: pkg.module,
      exports: 'named',
      banner
    },
    plugins: plugins
  }, {
    input: 'src/wrapper.js', // Path relative to package.json
    output: {
      format: 'iife',
      name: 'TreeVue',
      file: pkg.unpkg,
      exports: 'named',
      banner
    },
    plugins: [...plugins, uglify()]
  }, {
    input: 'src/wrapper.js', // Path relative to package.json
    output: {
      format: 'umd',
      file: pkg.main,
      name: 'TreeVue',
      exports: 'named',
      banner
    },
    plugins: [...plugins, uglify()]
  }
]