npm i svelte-ts-preprocess
import svelte from "rollup-plugin-svelte";
import resolve from "rollup-plugin-node-resolve";
import commonjs from "rollup-plugin-commonjs";
import { terser } from "rollup-plugin-terser";
import { preprocess } from "svelte-ts-preprocess";
const production = !process.env.ROLLUP_WATCH;
export default {
  input: "src/main.js",
  output: {
    sourcemap: true,
    format: "iife",
    name: "app",
    file: "public/bundle.js"
  },
  plugins: [
    svelte({
      // 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: css => {
        css.write("public/bundle.css");
      },
      preprocess: preprocess()
    }),
    // 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/rollup-plugin-commonjs
    resolve(),
    commonjs(),
    // If we're building for production (npm run build
    // instead of npm run dev), minify
    production && terser()
  ]
};
To install this monorepo you can use lerna + npm
cd svelte-ts-preprocess
npm i lerna -g
lerna bootstrap
or lerna + yarn see use workspaces
cd svelte-ts-preprocess
yarn i lerna -g
lerna bootstrap --use-workspaces
or yarn only
cd svelte-ts-preprocess
yarn install