rollup.config.js

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

const production = !process.env.ROLLUP_WATCH
const svelteConfig = require('./svelte.config')(production)

export default {
  input: 'src/main.js',
  output: {
    sourcemap: true,
    format: 'iife',
    name: 'app',
    file: 'public/build/bundle.js'
  },
  plugins: [
    svelte(svelteConfig),
    replace({
      // NOTE : Credits to Firthous
      // https://medium.com/@firthous.dev/how-to-setup-env-variables-to-your-svelte-js-app-c1579430f032
      process: JSON.stringify({
        env: {
          PROD: production,
          API_URL: production ? 'https://api.aposto.ch' : 'http://localhost:8080',
          APP_URL: production ? 'https://app.aposto.ch' : 'http://localhost:5000',
          AUTH_URL: production ? 'https://naturapeute.ch/api' : 'http://localhost:8000/api'
        }
      })
    }),

    // 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
  }
}

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
        })
      }
    }
  }
}