px2cfw but it's a special ncov api edition... demo: https://ncov-api-mirror.d2l.workers.dev/

px2cfw.js

addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request))
})
var BASE_URL = "https://lab.isaaclin.cn/nCoV";
var HOST_URL = "https://github.com/Dobby233Liu";
var HOST_NNM = "Dobby233Liu";
var CREDITS_HTML
 = `
由<a href="${HOST_URL}">${HOST_NNM}</a>镜像。此镜像根目录直通原api目录，无需添加/nCoV在目录名前（虽然会自动处理）。原api：<a href="${BASE_URL}">${BASE_URL}</a>。<hr />`
var CREDITS_INSERT_AFTER_FIRST_ENTRY_OF = `body > div > p`;
RegExp.escape = function(str) 
  {
    var specials = /[.*+?|()\[\]{}\\$^]/g; // .*+?|()[]{}\$^
    return str.replace(specials, "\\$&");
  }
var oneOccurenceHandled = false;
class ElementHandler {
  element(element) {
    if (oneOccurenceHandled) return;
    element.prepend(CREDITS_HTML, { html: true });
    oneOccurenceHandled = true;
  }
}
/**
 * Respond to the request
 * @param {Request} request
 */
async function handleRequest(request) {
  oneOccurenceHandled = false;
  var reqInit = {
    method: request.method,
    headers: request.headers,
    redirect: "follow"
  };
  var userPathName = new URL(request.url).pathname;
  if (userPathName.toLowerCase().startsWith("/ncov")) userPathName = userPathName.replace(new RegExp(RegExp.escape("/ncov"), "i"), "");
  if (!(userPathName.startsWith("/"))) userPathName = "/" + userPathName;
  console.info("goes to", userPathName);
  var doInsertMyCredits = false;
  if (userPathName == "/") doInsertMyCredits = true;
  try {
    if(request.method != "GET" && request.method != "HEAD") reqInit["body"] = request.body;
  } catch {}
  var returnValue;
  var fetchEntry = await fetch(BASE_URL + userPathName + new URL(request.url).search);
  returnValue = fetchEntry;
  if (doInsertMyCredits) {
    try {
      returnValue = new HTMLRewriter().on(CREDITS_INSERT_AFTER_FIRST_ENTRY_OF, new ElementHandler()).transform(fetchEntry);
    } catch (e) {
      console.error("fuck", e);
    }
  } 
  return returnValue;
}