rollup.config.js

import less from 'rollup-plugin-less';
import babel from 'rollup-plugin-babel';
import replace from 'rollup-plugin-replace';
import license from 'rollup-plugin-license';
import { uglify } from 'rollup-plugin-uglify';
import { eslint } from 'rollup-plugin-eslint';

module.exports = function(cli){
  const pkg = require('./package.json');

  const name = pkg.productTag;
  const mode = cli['config-mode'] || 'fast';
  const outname = cli['config-name'] || ( mode === 'min' ? `${name}.min` : name );
  const skin = cli['config-skin'] || 'material';

  const plugins = [
    replace({
      DEBUG: mode !== 'min',
      VERSION: pkg.version
    }),
    less({
      output: `dist/${name}.css`,
      option: {
        paths:[ `${__dirname}/sources/css/skins/${skin}` ]
      }
    }),
    license({
	    sourceMap: true,
	    thirdParty: {
		    allow(dependency) {
    		  return dependency.license === 'MIT';
		    },
      },
      banner: `@license
<%= pkg.productName %> v.<%= pkg.version %>

Copyright (c) <%= pkg.author.name %>. All rights reserved.

This work is licensed under the terms of the MIT license.  
For a copy, see <https://opensource.org/licenses/MIT>.`
    })
  ];

  let sourcemap = false;
  let treeshake = false;

  if (mode !== 'fastest'){
    plugins.push(eslint({}));
    plugins.push(babel({
      exclude: 'node_modules/**',
      presets: [
        [
          '@babel/preset-env',
          {
            loose: true,
            targets: { 'ie': '8' },
            exclude: [ 'transform-function-name' ]				
          }
        ]
      ]
    }));

    if (mode !== 'fast'){
      sourcemap = (mode === 'normal' || mode === 'min');
      treeshake = true;
    }
  }

  if (mode === 'min') {
    plugins.push(uglify({
      mangle:{
        properties:{ regex:/^_/ },
        reserved:['log', 'assert']
      },
      compress: {
        pure_funcs:['log', 'assert']
      }
    }));
  }

  return {
    treeshake,
    input: `sources/${name}.js`,
    plugins,
    output: {
      file: `dist/${outname}.js`,
      format: 'umd',
      name,
      sourcemap
    },
    watch: {
      chokidar: false,
      include: 'sources/**/*.js'
    }
  };
};