rollup.config.ts

import { builtinModules } from "module";
import { readFileSync } from "fs";

import typescript from "@rollup/plugin-typescript";
import copy from "rollup-plugin-copy";
import del from "rollup-plugin-delete";
import json from "@rollup/plugin-json";

import type { Plugin, WarningHandlerWithDefault } from "rollup";

const onwarn: WarningHandlerWithDefault = (warning) => {
  console.error(
    "Building Rollup produced warnings that need to be resolved. " +
      "Please keep in mind that the browser build may never have external dependencies!"
  );
  throw Object.assign(new Error(), warning);
};

const emitModulePackageFile = (): Plugin => {
  return {
    name: "emit-module-package-file",
    generateBundle() {
      this.emitFile({
        type: "asset",
        fileName: "package.json",
        source: `{"type":"module"}`,
      });
    },
  };
};

// eslint-disable-next-line @typescript-eslint/no-explicit-any
const defineConfig = (pkg: Record<string, any>) => {
  return {
    input: "src/index.ts",
    external: Object.keys(pkg.dependencies || {})
      .concat(Object.keys(pkg.peerDependencies || {}))
      .concat(builtinModules),
    onwarn,
    strictDeprecations: true,
    output: [
      {
        format: "cjs",
        file: pkg.main,
        exports: "named",
        footer: "module.exports = Object.assign(exports.default, exports);",
        sourcemap: true,
      },
      {
        format: "es",
        file: pkg.module,
        plugins: [emitModulePackageFile()],
        sourcemap: true,
      },
    ],
    plugins: [
      typescript({ sourceMap: true }),
      copy({
        targets: [{ src: "types/index.d.ts", dest: "dist/types" }],
        verbose: true,
      }),
      del({ targets: "dist/*", runOnce: true }),
      json(),
    ],
  };
};

export default defineConfig(
  JSON.parse(readFileSync(new URL("./package.json", import.meta.url), "utf8"))
);