tsup.config.ts

import { defineConfig, Options } from "tsup";
import fs from "fs";
import path from "path";

// Using the work from mark
// https://github.com/reduxjs/redux/blob/c9e06506f88926e252daf5275495eba0c04bf8e3/tsup.config.ts#L2
// https://blog.isquaredsoftware.com/2023/08/esm-modernization-lessons/

export function createConfig() {
  return defineConfig((options: Options) => {
    const pkgJson = JSON.parse(fs.readFileSync("package.json", "utf8"));

    const defaultOptions: Options = {
      entry: [pkgJson.main],
      sourcemap: true,
      ...options,
    };

    if (process.env.PLAYER_NATIVE_BUNDLE) {
      const bundleEntryName = process.env.PLAYER_NATIVE_BUNDLE;
      const bundleFileTarget = path.join(
        "dist",
        bundleEntryName + ".native.js",
      );
      return [
        {
          ...defaultOptions,
          globalName: bundleEntryName,
          external: [],
          define: {
            "process.env.NODE_ENV": JSON.stringify("production"),
          },
          target: "es5",
          format: ["iife"],
          async onSuccess() {
            await fs.promises.copyFile(
              "dist/index.global.js",
              bundleFileTarget,
            );
            await fs.promises.copyFile(
              "dist/index.global.js.map",
              bundleFileTarget + ".map",
            );

            await fs.promises.rm("dist/index.global.js");
            await fs.promises.rm("dist/index.global.js.map");
          },
        },
      ];
    }

    return [
      {
        ...defaultOptions,
        format: ["esm"],
        outExtension: () => ({ js: ".mjs", dts: ".d.mts" }),
        clean: true,
        async onSuccess() {
          // Support Webpack 4 by pointing `"module"` to a file with a `.js` extension
          fs.copyFileSync("dist/index.mjs", "dist/index.legacy-esm.js");
        },
      },
      // Browser-ready ESM, production + minified
      {
        ...defaultOptions,
        define: {
          "process.env.NODE_ENV": JSON.stringify("production"),
        },
        format: ["esm"],
        outExtension: () => ({ js: ".mjs" }),
      },
      {
        ...defaultOptions,
        format: "cjs",
        outDir: "./dist/cjs/",
        outExtension: () => ({ js: ".cjs" }),
      },
    ];
  });
}