rollup.config.js

import svelte from "rollup-plugin-svelte";
import resolve from "rollup-plugin-node-resolve";
import browsersync from "rollup-plugin-browsersync";
import { terser } from "rollup-plugin-terser";
import commonjs from "rollup-plugin-commonjs";
import pkg from "./package.json";
import sveltePreprocess from "svelte-preprocess";
import postcss from "rollup-plugin-postcss";

const watch = process.env.WATCH;
const mainpath = watch ? "docs/index.js" : pkg.main;
const dedupe = importee =>
  importee === "svelte" || importee.startsWith("svelte/");

const scssOptions = {
  transformers: {
    scss: {
      includePaths: ["node_modules", "src"]
    },
    postcss: {
      plugins: [require("autoprefixer")]
    }
  }
};

export default {
  // input: "src/index.js",
  input: "index.js",
  output: [
    { file: pkg.module, format: "es" },
    { file: mainpath, format: "iife" }
  ],
  plugins: [
    commonjs(),
    svelte({
      preprocess: sveltePreprocess(scssOptions)
    }),
    resolve({
      dedupe
    }),
    postcss(),
    watch && browsersync({ server: "docs" }),
    !watch && terser()
  ]
};