rollup.config.js

// Dependencies
// =============================================================================
const path = require('path');

import { babel } from '@rollup/plugin-babel';
import commonjs from '@rollup/plugin-commonjs';
import { eslint } from 'rollup-plugin-eslint';
import json from '@rollup/plugin-json';
import mergician from 'mergician';
import pkg from './package.json';
import { nodeResolve } from '@rollup/plugin-node-resolve';
import { terser } from 'rollup-plugin-terser';


// Settings
// =============================================================================
// Copyright
const currentYear = (new Date()).getFullYear();
const releaseYear = 2022;

// Output
const entryFile = path.resolve(__dirname, 'src', 'js', 'index.js');
const outputFile = path.resolve(__dirname, 'dist', `${pkg.name}.js`);

// Banner
const bannerData = [
  `${pkg.name}`,
  `v${pkg.version}`,
  `${pkg.homepage}`,
  `(c) ${releaseYear}${currentYear === releaseYear ? '' : '-' + currentYear} ${pkg.author}`,
  `${pkg.license} license`
];

// Plugins
const pluginSettings = {
  eslint: {
    exclude: ['node_modules/**', './package.json'],
    throwOnWarning: false,
    throwOnError: true
  },
  babel: {
    // See .babelrc
    babelHelpers: 'bundled'
  },
  terser: {
    beautify: {
      compress: false,
      mangle: false,
      output: {
        beautify: true,
        comments: /(?:^!|@(?:license|preserve))/
      }
    },
    minify: {
      compress: true,
      mangle: true,
      output: {
        comments: new RegExp(pkg.name)
      }
    }
  }
};


// Config
// =============================================================================
// Base
const config = {
  input: entryFile,
  output: {
    banner: `/*!\n * ${bannerData.join('\n * ')}\n */`,
    file: outputFile,
    sourcemap: true
  },
  plugins: [
    nodeResolve(),
    commonjs(),
    json(),
    eslint(pluginSettings.eslint),
    babel(pluginSettings.babel)
  ],
  watch: {
    clearScreen: false
  }
};

// Formats
// -----------------------------------------------------------------------------
// IIFE
const iife = mergician({}, config, {
  output: {
    format: 'iife'
  },
  plugins: config.plugins.concat([
    terser(pluginSettings.terser.beautify)
  ])
});

// IIFE (Minified)
const iifeMinified = mergician({}, config, {
  output: {
    file: iife.output.file.replace(/\.js$/, '.min.js'),
    format: iife.output.format
  },
  plugins: config.plugins.concat([
    terser(pluginSettings.terser.minify)
  ])
});


// Exports
// =============================================================================
export default [
  iife,
  iifeMinified
];