utils.js

export async function concurrent(iterable, iteratorFn, limit = 200) {
  const executing = [];

  for await (const item of iterable) {
    const p = iteratorFn(item).then(() =>
      executing.splice(executing.indexOf(p), 1)
    );

    executing.push(p);

    if (executing.length >= limit) {
      await Promise.race(executing);
    }
  }

  await Promise.all(executing);
}

export const mimes = new Map([
  [".html", "text/html; charset=utf-8"],
  [".txt", "text/plain; charset=utf-8"],
  [".js", "text/javascript; charset=utf-8"],
  [".css", "text/css; charset=utf-8"],
  [".json", "application/json; charset=utf-8"],
  [".ico", "image/x-icon"],
  [".png", "image/png"],
  [".jpg", "image/jpg"],
  [".jpeg", "image/jpg"],
  [".gif", "image/gif"],
  [".svg", "image/svg+xml"],
  [".mp3", "audio/mpeg"],
  [".mp4", "video/mpeg"],
  [".xml", "text/xml"],
  [".woff", "font/woff"],
  [".woff2", "font/woff2"],
  [".wasm", "application/wasm"],
  [".webp", "image/webp"],
  [".webm", "video/webm"],
  [".zip", "application/zip"],
]);