rollup.config.js

// @ts-check

import path from "node:path";
import process from "node:process";
import fs from "node:fs";
import { defineConfig } from "rollup";
import terser from "@rollup/plugin-terser";
import nodeResolve from "@rollup/plugin-node-resolve";
import replace from "@rollup/plugin-replace";
import esbuild from "rollup-plugin-esbuild";

const extensions = [".js", ".ts"];
const { root } = path.parse(process.cwd());

/**
 * @param {string} id
 * @returns {boolean}
 */
function external(id) {
  return !id.startsWith(".") && !id.startsWith(root);
}

/**
 * @param {string} input
 * @param {string} output
 * @returns {import("rollup").RollupOptions}
 */
function createESMConfig(input, output) {
  return {
    external,
    input,
    output: {
      file: output,
      format: "esm",
      sourcemap: true,
    },
    plugins: [
      esbuild({
        target: "es2022",
      }),
      nodeResolve({ extensions }),
      replace({
        "import.meta.vitest": "undefined",
        "preventAssignment": false,
      }),
      terser({
        compress: {
          ecma: 2020,
          passes: 5,
        },
        ecma: 2020,
        format: {
          comments: false,
        },
        nameCache: {},
        toplevel: true,
      }),
    ],
  };
}

const srcPath = path.join(process.cwd(), "src");

/**
 * @returns {string[]}
 */
function files() {
  try {
    const items = fs.readdirSync(srcPath);

    const fileNames = items
      .filter(item => fs.statSync(path.join(srcPath, item)).isFile())
      .map(item => path.parse(item).name);

    return fileNames;
  }
  catch (err) {
    console.error("Error reading directory:", err);
    return [];
  }
}

export default defineConfig(files().filter(file => file !== "types").flatMap(file => [
  createESMConfig(`src/${file}.ts`, `dist/${file}.js`),
]));