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'

const production = !process.env.ROLLUP_WATCH

export default {
  input: 'src/main.ts',
  output: {
    sourcemap: !production,
    format: 'iife',
    name: 'app',
    file: 'public/bundle.js'
  },
  plugins: [
    svelte({
      preprocess: sveltePreprocess({ sourceMap: !production }),
      compilerOptions: {
        dev: !production
      }
    }),
    css({ output: 'bundle.css' }),
    resolve({
      browser: true,
      dedupe: ['svelte']
    }),
    commonjs(),
    typescript({
      sourceMap: !production,
      inlineSources: !production
    }),
    !production && livereload('public'),
    production && terser()
  ],
  watch: {
    clearScreen: false
  }
}