update

js/excel.js

@@ -1,15 +1,17 @@
 
 
 exceltoxlxstream = async function (file) {
-    if (file) {
-        const reader = new FileReader();
-        reader.onload = async function (e) {
-            const data = new Uint8Array(e.target.result);
-            const workbook = XLSX.read(data, { type: 'array' });
-            const fileStream = XLSX.write(workbook, { type: 'array', bookType: 'xlsx' });
-            return fileStream;
-        };
-        reader.readAsArrayBuffer(file);
-    }
+    return new Promise(resolve => {
+        if (file) {
+            const reader = new FileReader();
+            reader.onload = async function (e) {
+                const data = new Uint8Array(e.target.result);
+                const workbook = XLSX.read(data, { type: 'array' });
+                const fileStream = XLSX.write(workbook, { type: 'array', bookType: 'xlsx' });
+                resolve(fileStream);
+            };
+            reader.readAsArrayBuffer(file);
+        }
+    });
 }