rollup.config.js

import resolve from "rollup-plugin-node-resolve";
import replace from "rollup-plugin-replace";
import commonjs from "rollup-plugin-commonjs";
import svelte from "rollup-plugin-svelte";
import { terser } from "rollup-plugin-terser";
import config from "sapper/config/rollup";
import pkg from "./package.json";


const mode = process.env.NODE_ENV;
const dev = mode === "development";

const onwarn = (warning, onwarn) => (warning.code === "CIRCULAR_DEPENDENCY" && /[/\\]@sapper[/\\]/.test(warning.message)) || onwarn(warning);
const dedupe = (importee) => importee === "svelte" || importee.startsWith("svelte/");

export default {
  client: {
    input: config.client.input(),
    output: config.client.output(),
    plugins: [
      replace({
        "process.browser": true,
        "process.env.NODE_ENV": JSON.stringify(mode)
      }),
      svelte({
        dev,
        hydratable: true,
        emitCss: true
      }),
      resolve({
        browser: true,
        dedupe
      }),
      commonjs(),

      !dev && terser({
        module: true
      })
    ],

    onwarn
  },

  server: {
    input: config.server.input(),
    output: config.server.output(),
    plugins: [
      replace({
        "process.browser": false,
        "process.env.NODE_ENV": JSON.stringify(mode)
      }),
      svelte({
        generate: "ssr",
        dev
      }),
      resolve({
        dedupe
      }),
      commonjs()
    ],
    external: Object.keys(pkg.dependencies).concat(
      require("module").builtinModules || Object.keys(process.binding("natives"))
    ),

    onwarn
  },

  serviceworker: {
    input: config.serviceworker.input(),
    output: config.serviceworker.output(),
    plugins: [
      resolve(),
      replace({
        "process.browser": true,
        "process.env.NODE_ENV": JSON.stringify(mode)
      }),
      commonjs(),
      !dev && terser()
    ],

    onwarn
  }
};