rollup.config.js

import svelte from 'rollup-plugin-svelte';
import commonjs from '@rollup/plugin-commonjs';
import resolve from '@rollup/plugin-node-resolve';
import livereload from 'rollup-plugin-livereload';
import { terser } from 'rollup-plugin-terser';
import css from 'rollup-plugin-css-only';

const production = !process.env.ROLLUP_WATCH;

function serve() {
	let server;

	function toExit() {
		if (server) server.kill(0);
	}

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

			process.on('SIGTERM', toExit);
			process.on('exit', toExit);
		}
	};
}



export default [
	{
	  input: "src/main.js",
	  output: {
		sourcemap: true,
		format: "iife",
		name: "app",
		file: "public/build/bundle.js",
	  },
	  plugins: [
		svelte({
		  compilerOptions: {
			// enable run-time checks when not in production
			dev: !production,
		  },
		}),
		// we'll extract any component CSS out into
		// a separate file - better for performance
		css({ output: "bundle.css" }),
  
		// 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"],
		}),
		commonjs(),
  
		// 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
		production && terser(),
	  ],
	  watch: {
		clearScreen: false,
	  },
	},

	{
	  input: "src/select.js",
	  output: {
		sourcemap: true,
		format: "iife",
		file: "public/build/select.js",
	  },
	  plugins: [resolve(), commonjs()],
	  watch: {
		clearScreen: false,
	  },
	},
	

  ];