show-body-length.ts

addEventListener("fetch", (e) => {
  e.respondWith((async () => {
    let result: string;
    const { request } = e;
    if (request.body == null) {
      result = "request body is empty\n";
    } else {
      result = `request body length = ${(await request.arrayBuffer()).byteLength}\n`;
    }
    return new Response(result)
  })());
});