I have a working rollup.config.js file but need to run a separate packaging script after Rollup is done. My plan was to use Rollup's watchers via their JS API. However, I cannot get the JS API to work at all.

I am referencing this code from the Rollup site...

```
const loadConfigFile = require('rollup/dist/loadConfigFile');
const path = require('path');
const rollup = require('rollup');

loadConfigFile(path.resolve(__dirname, 'rollup.config.js'))
  .then(async ({options, warnings}) => {
    warnings.flush();
    const bundle = await rollup.rollup(options);
    await Promise.all(options.output.map(bundle.write));
    rollup.watch(options);
  })

```

but I keep getting an error `Unknown input options: 0.......Error: You must supply options.input to rollup`

My rollup.config.js is as follow...

```
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 replace from '@rollup/plugin-replace';
import json from '@rollup/plugin-json';

const production = !process.env.ROLLUP_WATCH;

export default {
    input: 'src/main.js',
    output: {
        sourcemap: true,
        format: 'iife',
        name: 'app',
        file: 'public/bundle.js'
    },
    plugins: [
        json(),
        production && replace({
            'eruda': ``,
            exclude: 'node_modules/**',
            delimiters: ['import * as eruda from \'', '\'']
        }),
        production && replace({
            'eruda': ``,
            exclude: 'node_modules/**',
            delimiters: ['', '.init()']
        }),
        svelte({
            dev: !production,
            css: css => {
                css.write('public/bundle.css');
            }
        }),
        resolve({ browser: true }),
        commonjs(),

        !production && livereload('public'),
        production && terser()
    ],
    watch: {
        clearScreen: false
    }
};

```

Any thoughts are appreciated!