Svelte rollup.config.js with multiple bundles

note.md

The adjacent file is identical to the one provided by the Svelte 3.x library (3.46.x-ish) with the following distinctions:

1. I updated the config with a little help from the docs to create a separate bundle for each .ts file in the src/ directory.
2. I ran the provided script that adds TypeScript support.
3. I updated the output.file property to point to the build directory in the parent (this is nested in a bigger Gradle project).

Note that you'll still need to create a separate .ts file (analogous to the initial main.ts) for each bundle.

Hope someone finds this useful.

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 sveltePreprocess from 'svelte-preprocess';
import typescript from '@rollup/plugin-typescript';
import css from 'rollup-plugin-css-only';
import { readdirSync } from 'fs';

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);
		}
	};
}

const entryPoints = readdirSync('src')
	.filter(f => f.endsWith('.ts'))
	.filter(f => !f.endsWith('.d.ts'))
	.map(f => f.substring(0, f.indexOf('.ts')));

export default entryPoints.map(name => {
	return {
		input: `src/${name}.ts`,
		output: {
			sourcemap: !production,
			format: 'iife',
			name: 'app',
			file: `../build/resources/main/public/${name}.js`
		},
		plugins: [
			svelte({
				preprocess: sveltePreprocess({ sourceMap: !production }),
				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: `${name}.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(),
			typescript({
				sourceMap: !production,
				inlineSources: !production
			}),
	
			// 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
		}
	};
});