code: function fetchDetails(event) {
      var filename = event.filename || event.target && event.target.src;
      if (scriptPromises[filename]) {
  
        /* Only process this once... */
        if (event.stopPropagation) event.stopPropagation();
        if (event.preventDefault) event.preventDefault();
  
        /* Try to zap the <script /> element */
        if (event.target && event.target.parentNode) try {
          event.target.parentNode.removeChild(event.target);
        } catch (error) {
          // This might have never slapped in the DOM
        }
  
        /* Wipe-and-return... */
        var promise = scriptPromises[filename];
        delete scriptPromises[filename];
        promise.remaining -= 1; // decrement!
        return { script: filename, promise: promise };
      }
    }
docs: /* Fetch and remove the promise