text: export enum DropEffect {
      none = "none",
      link = "link",
      copy = "copy",
      move = "move",
  }
  
  /**
   * Helper functions for drag and drop
   */
  export class DragUtils {
      /**
       * Call this in the draghover callback to allow/disallow dropping
       */
      public static allowDrop(event: DragEvent, allowed: boolean, effect: DropEffect = DropEffect.move) {
          if (!allowed) { return; }
          event.dataTransfer!.dropEffect = effect;
          event.stopPropagation();
          event.preventDefault();
      }
  }
  