title: Rollup Build seems to be overly large for component library
body: <p>I am using rollup (v2.13.1), and it all works fine exporting out my React Library, BUT, I believe that I am using the WHOLE library in my vendor js file and NOT just the components I am using.
  The library seems a bit large when I run tool analyze. Seems I'm not properly doing modules, or ?</p>
  <p>package.json build command: &quot;build&quot;: &quot;rollup -c&quot;,</p>
  <p>Here is my Rollup config, anything I am missing or doing incorrectly?</p>
  <pre><code>And I am using it in a seperate application like so:
  import { Button, Icon } from &quot;myReactLibrary&quot;;
  </code></pre>
  <p>CODE: Rollup Config</p>
  <pre><code>import peerDepsExternal from 'rollup-plugin-peer-deps-external';
  import resolve from 'rollup-plugin-node-resolve';
  import typescript from 'rollup-plugin-typescript2';
  import commonjs from 'rollup-plugin-commonjs';
  import copy from 'rollup-plugin-copy';
  import postcss from 'rollup-plugin-postcss';
  const packageJson = require('./package.json');
  
  export default {
    input: 'src/index.ts',
    output: [
      {
        dir: packageJson.main,
        format: 'cjs',
        sourcemap: true,
      },
      {
       dir: packageJson.module,
       format: 'esm',
       sourcemap: true,
     },
  ],
   plugins: [
     peerDepsExternal(),
     typescript({useTsconfigDeclarationDir: true}),
     resolve(),
     commonjs(),
     postcss({
      modules: true,
     }),
    copy({
      targets: [
        {
          src: 'src/styles/colors.scss',
          dest: 'build',
          rename: 'colors.scss',
        },
      {
        src: 'src/styles/helpers.scss',
        dest: 'build',
        rename: 'helpers.scss',
      },
      {
        src: 'src/styles/mixins.scss',
        dest: 'build',
        rename: 'mixins.scss',
      },
    ],
  }),
   ],
  };
  </code></pre>
  <p>And the &quot;src/index.ts&quot; file is:</p>
  <pre><code>  import Accordion from './Accordion/Accordion';
    import AccordionGroup from './Accordion/AccordionGroup';
    import Avatar from './Avatar/Avatar';
    import Button, {BUTTON_THEMES} from './Button/Button';
    import Checkbox from './Checkbox/Checkbox';
    import CheckboxGroup from './Checkbox/CheckboxGroup';
    import Form from './Form/Form';
    import {Size as ELEMENT_SIZE} from './base.types';
    import Grid, {BREAKPOINTS} from './Grid/Grid';
    import Icon from './Icon/Icon';
    import InputField from './Input/Input';
    import {LoaderComponent, LoaderPage} from './Loaders/Loaders';
    import Modal from './Modal/Modal';
    import Panel from './Panel/Panel';
    import PlainModal from './PlainModal/PlainModal';
    import Radio from './Radio/Radio';
     import RadioGroup from './Radio/RadioGroup';
    import SelectField from './SelectField/SelectField';
    import {SelectOptions, SelectArrayOptions, SelectBaseOption, SelectGroupOptions} from   './SelectField/SelectField.types';
    import TextArea from './TextArea/TextArea';
    import {Label, ErrorMessage} from './Parts';
  
   export {
      Accordion,
      AccordionGroup,
      Avatar,
      Button,
      BUTTON_THEMES,
      Checkbox,
      CheckboxGroup,
      ELEMENT_SIZE,
      ErrorMessage,
      Form,
      Grid,
      BREAKPOINTS,
      Icon,
      InputField,
      Label,
      LoaderComponent,
      LoaderPage,
      Modal,
      Panel,
      PlainModal,
      Radio,
      RadioGroup,
      SelectField,
      SelectOptions,
      SelectArrayOptions,
      SelectBaseOption,
      SelectGroupOptions,
      TextArea,
    };
  </code></pre>