laod a script and await until it is loaded, superseeded by loadDependency.await.js

loadScript.await.js

/**
 * Nabil Redmann (BananaAcid), License MIT
 */
async function loadScript(url) {
  // check if it was added already
  if (document.querySelectorAll(`script[src="${url}"]`).length) return true;

  // load if missing
  let script = document.createElement('script');
  script.src = url;
  (document.head || document.body).appendChild(script);
  
  // wait for it to be loaded or failed.
  let done = await new Promise( (resolve, reject) => {script.onload = resolve; script.onerror = reject;} )
                    .then(_=> true).catch(_=> false);
  return done;
}


let getTime = async _ => {

  let done = await loadScript('https://cdn.jsdelivr.net/npm/luxon@3.0.4/build/global/luxon.min.js');
  if (done)
      console.log('added script, global is now available', window.luxon);
    else
      console.error('could not add script');
  
  
  
  // use if available
  if (window.luxon) {
    let time = window.luxon.DateTime.now()/*.setZone('Europe/Berlin') or current by default*/.toISO();
    console.log('time-iso', time);
  }
}

// trigger
getTime();