Getting "Uncaught SyntaxError: Unexpected token 'export'" when running rollup.js with svelte and format: es

Question

I've tried so many of these format exports and keep running into different issues. Running the app in Chrome, so modern browsers

import svelte from 'rollup-plugin-svelte';
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
import livereload from 'rollup-plugin-livereload';
import { terser } from 'rollup-plugin-terser';
import json from '@rollup/plugin-json';
// import typescript from '@rollup/plugin-typescript';
import autoPreprocess from 'svelte-preprocess';
import { scss } from 'svelte-preprocess';

const production = !process.env.ROLLUP_WATCH;

export default {
  input: 'src/main.js',
  output: [
    {
      sourcemap: true, // this would be dev/pre-prod only, not for prod
      // export type InternalModuleFormat = 'amd' | 'cjs' | 'es' | 'iife' | 'system' | 'umd';
      format: 'es', // cjs is commonjs, which is legacy bundle types
      name: 'app',
      dir: 'public/build',
    },
    // SystemJS version, for older browsers
    {
      dir: "public/build/nomodule",
      format: "system",
      sourcemap: true
    },
  ],
  experimentalCodeSplitting: true,
  experimentalDynamicSupport: true,
  // list of all the plugins
  // https://github.com/rollup/plugins
  plugins: [
    svelte({
      // this will create a custom web component for embedding, future usage
      // customElement: true,

      // enable run-time checks when not in production
      dev: !production,

      // this autoPreprocess runs all kinds things such as ts and scss support
      preprocess: autoPreprocess(),
    }),

    // If you have external dependencies installed from
    // npm, you'll most likely need these plugins. In
    // some cases you'll need additional configuration -
    // consult the documentation for details:
    // https://github.com/rollup/plugins/tree/master/packages/commonjs
    resolve({
      browser: true,
      dedupe: ['svelte'],
    }),

    // this allows support for older module types which would be quite common in the node_modules dependencies, versus esm modules
    commonjs(),

    // this allows import of json files, such a configuration or data into files
    json(),

    // this allows ts support, although i'm not sure we need this since i think autoPreprocess does this
    // typescript(),

    // In dev mode, call `npm run start` once
    // the bundle has been generated
    !production && serve(),

    // Watch the `public` directory and refresh the
    // browser on changes when not in production
    !production && livereload('public'),

    // If we're building for production (npm run build
    // instead of npm run dev), minify
    // terser is a fork of uglify and does all the minification
    production && terser(),
  ],
  watch: {
    clearScreen: false,

    // don't spend the cycles to watch/monitor node_modules.  when you install node modules, it won't trigger the watch.  You must stop/start again
    exclude: ['node_modules/**'],
  },
};

function serve() {
  let started = false;

  return {
    writeBundle() {
      if (!started) {
        started = true;

        require('child_process').spawn('npm', ['run', 'start', '--', '--dev'], {
          stdio: ['ignore', 'inherit', 'inherit'],
          shell: true,
        });
      }
    },
  };
}