blocker.js

import "whatwg-fetch";

const BLOCKER_TEST_URL =
  "https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js";

const detectBlocker = callback => {
  fetch(
    new Request(BLOCKER_TEST_URL, {
      method: "HEAD",
      mode: "no-cors"
    })
  )
    .then(function(response) {
      return response;
    })
    .then(function(res) {
      callback(false);
    })
    .catch(function(e) {
      callback(true);
    });
};

export default detectBlocker;