Reads fetched response with declared charset

web.js

/**
 * Reads the response text in given text encoding. 
 * When charset isn't defined on `content-type` header it falls back to `utf-8`.   
 * @param {Response} resp
 * @returns {string}
 */
async function readTextResponse(resp) {
  const contentType = resp.headers.get("content-type");
  const [, charset] = contentType?.split("charset=");
  const decoder = new TextDecoder(charset ?? "utf-8");
  const buffer = await resp.arrayBuffer();
  return decoder.decode(buffer);
}