rollup.config.js

import babel from 'rollup-plugin-babel';
import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import minify from 'rollup-plugin-babel-minify';
import builtins from 'rollup-plugin-node-builtins';
import polyfill from 'rollup-plugin-polyfill';
import pkg from './package.json';

const MAIN = 'src/flighty.js';

const ABORT_POLYFILL = 'abortcontroller-polyfill/dist/polyfill-patch-fetch';
const CROSS_FETCH_POLYFILL = 'cross-fetch/polyfill';

const EXTERNAL_POLYFILLS = [ABORT_POLYFILL, CROSS_FETCH_POLYFILL];

const browserPlugins = [
  resolve({ browser: true }),
  commonjs(),
  babel(),
  minify({ comments: false }),
  builtins(),
];

const es5Plugins = [
  commonjs(),
  babel(),
];

const polyfillAll = () => polyfill(
  MAIN,
  [
    'promise-polyfill',
    CROSS_FETCH_POLYFILL,
    ABORT_POLYFILL,
  ],
);

const polyfillAbort = () => polyfill(
  MAIN,
  [
    ABORT_POLYFILL,
  ],
);

export default [
  // With dependencies, no polyfills
  // Browser
  {
    input: MAIN,
    output: {
      file: 'dist/flighty.browser.min.js',
      format: 'iife',
      name: 'flighty',
    },
    external: [],
    plugins: [...browserPlugins],
  },

  // ES5
  {
    input: MAIN,
    output: {
      file: 'dist/flighty.js',
      format: 'cjs',
    },
    external: [
      ...EXTERNAL_POLYFILLS,
      ...Object.keys(pkg.dependencies || {}),
      ...Object.keys(pkg.peerDependencies || {}),
    ],
    plugins: [
      ...es5Plugins,
    ],
  },

  // Include polyfills for fetch, promise, and AbortController
  // unpkg.com?
  {
    input: MAIN,
    output: {
      file: 'fetch/index.js',
      format: 'iife',
      name: 'flighty',
    },
    external: [],
    plugins: [
      polyfillAll(),
      ...browserPlugins],
  },

  // Other
  {
    input: MAIN,
    output: {
      file: 'dist/flighty.fetch.js',
      format: 'cjs',
    },
    external: [
      ...EXTERNAL_POLYFILLS,
      ...Object.keys(pkg.dependencies || {}),
      ...Object.keys(pkg.peerDependencies || {}),
    ],
    plugins: [
      polyfillAll(),
      ...es5Plugins,
    ],
  },

  // Module
  {
    input: MAIN,
    output: {
      file: 'src/flighty.fetch.js',
      format: 'esm',
    },
    external: [
      ...EXTERNAL_POLYFILLS,
      ...Object.keys(pkg.dependencies || {}),
      ...Object.keys(pkg.peerDependencies || {}),
    ],
    plugins: [
      polyfillAll(),
    ],
  },


  // Include polyfills for AbortController
  // put an index.js file in abort for the benefit of unpkg.com?
  {
    input: MAIN,
    output: {
      file: 'abort/index.js',
      format: 'iife',
      name: 'flighty',
    },
    external: [],
    plugins: [
      polyfillAbort(),
      ...browserPlugins,
    ],
  },

  {
    input: MAIN,
    output: {
      file: 'dist/flighty.abort.js',
      format: 'cjs',
    },
    external: [
      ...EXTERNAL_POLYFILLS,
      ...Object.keys(pkg.dependencies || {}),
      ...Object.keys(pkg.peerDependencies || {}),
    ],
    plugins: [
      polyfillAbort(),
      ...es5Plugins,
    ],
  },

  // Include polyfills for AbortController
  {
    input: MAIN,
    output: {
      file: 'src/flighty.abort.js',
      format: 'esm',
    },
    external: [
      ...EXTERNAL_POLYFILLS,
      ...Object.keys(pkg.dependencies || {}),
      ...Object.keys(pkg.peerDependencies || {}),
    ],
    plugins: [
      polyfillAbort(),
    ],
  },
];