export const insertScript = (id, src, onload) => {
  // script is already inserted, do nothing
  if (document.getElementById(id)) return;

  // insert script
  const firstScriptTag = document.getElementsByTagName('script')[0];
  const scriptTag = document.createElement('script');
  scriptTag.id = id;
  scriptTag.onload = onload;
  scriptTag.src = src;
  scriptTag.defer = true;
  scriptTag.async = true;
  firstScriptTag.parentNode.insertBefore(scriptTag, firstScriptTag);
};