const app = createApp({
     setup() {
         const loading = ref(false);
         const error = ref(null);
         const hasFile = ref(true);

         const onView = async (item) => {
             const iframe = document.getElementById('frameContainer');
             if (!iframe) return;

             loading.value = true;
             error.value = '';

             let img1 = '/temp/' + item.ImageFileName;
             const urls = [img1]; //传入一个或多个文件路径。
             const results = await Promise.all(urls.map(checkFileExists))
             hasFile.value = results[0];


             if (hasFile.value) {
                 iframe.src = img1;
             }
         }

         const checkFileExists = async (url) => {
             try {
                 const res = await fetch(url, {
                     method: 'HEAD',
                     cache: 'no-store',
                 })
                 return res.ok
             } catch (err) {
                 return false
             }
         };

         return {
             loading,
             error,
             hasFile,
             onView
         };
     }
 });

 app.mount('#app');