rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import commonjs from 'rollup-plugin-commonjs';
import babel from 'rollup-plugin-babel';
import pkg from './package.json';
import postcss from 'rollup-plugin-postcss'
const pluginsConfig = [
      postcss({}),
      babel({
        exclude: 'node_modules/**',
        runtimeHelpers: true ,
        babelrc: false,
        presets: [["@babel/preset-env", { modules: false }], ["react-app", {flow:true}]],
        plugins: [
          "@babel/plugin-proposal-class-properties",
          "@babel/plugin-proposal-export-default-from",
          "@babel/plugin-proposal-logical-assignment-operators",
          ["@babel/plugin-proposal-optional-chaining", { loose: false }],
          ["@babel/plugin-proposal-pipeline-operator", { proposal: "minimal" }],
          ["@babel/plugin-proposal-nullish-coalescing-operator", { loose: false }],
          "@babel/plugin-proposal-do-expressions"
        ]
      }),
      resolve({

    // the fields to scan in a package.json to determine the entry point
    // if this list contains "browser", overrides specified in "pkg.browser"
    // will be used
    mainFields: ['module', 'main'], // Default: ['module', 'main']

    // DEPRECATED: use "mainFields" instead
    // use "module" field for ES6 module if possible
    module: true, // Default: true

    // DEPRECATED: use "mainFields" instead
    // use "jsnext:main" if possible
    // legacy field pointing to ES6 module in third-party libraries,
    // deprecated in favor of "pkg.module":
    // - see: https://github.com/rollup/rollup/wiki/pkg.module
    jsnext: true,  // Default: false

    // DEPRECATED: use "mainFields" instead
    // use "main" field or index.js, even if it's not an ES6 module
    // (needs to be converted from CommonJS to ES6)
    // – see https://github.com/rollup/rollup-plugin-commonjs
    main: true,  // Default: true

    // some package.json files have a "browser" field which specifies
    // alternative files to load for people bundling for the browser. If
    // that's you, either use this option or add "browser" to the
    // "mainfields" option, otherwise pkg.browser will be ignored
    browser: true,  // Default: false

    // not all files you want to resolve are .js files
    extensions: ['.mjs', '.js', '.jsx', '.json'],  // Default: [ '.mjs', '.js', '.json', '.node' ]

    // whether to prefer built-in modules (e.g. `fs`, `path`) or
    // local ones with the same names
    preferBuiltins: false,  // Default: true

    // Lock the module search in this path (like a chroot). Module defined
    // outside this path will be marked as external
    jail: '/my/jail/path', // Default: '/'

    // Set to an array of strings and/or regexps to lock the module search
    // to modules that match at least one entry. Modules not matching any
    // entry will be marked as external
    only: ['some_module', /^@some_scope\/.*$/], // Default: null

    // If true, inspect resolved files to check that they are
    // ES2015 modules
    modulesOnly: true, // Default: false

    // Force resolving for these modules to root's node_modules that helps
    // to prevent bundling the same package multiple times if package is
    // imported from dependencies.
    dedupe: ['react', 'react-dom'], // Default: []

    // Any additional options that should be passed through
    // to node-resolve
    customResolveOptions: {
      moduleDirectory: 'js_modules'
    }
      }), // so Rollup can find `ms`
      commonjs() // so Rollup can convert `ms` to an ES module
    ]

export default [
  // browser-friendly UMD build
  {
    input: 'src/editor/components/Dante/Dante.js',
    output: {
      name: 'Dante',
      file: pkg.browser,
      format: 'umd'
    },
    plugins: pluginsConfig
  },

  // CommonJS (for Node) and ES module (for bundlers) build.
  // (We could have three entries in the configuration array
  // instead of two, but it's quicker to generate multiple
  // builds from a single configuration where possible, using
  // an array for the `output` option, where we can specify 
  // `file` and `format` for each target)
  {
    input: 'src/editor/components/Dante/Dante.js',
    external: ['ms'],
    output: [
      { file: pkg.main, format: 'cjs' },
      { file: pkg.module, format: 'es' }
    ],
    plugins: pluginsConfig
  }
];