edit

assets/lib/excel/excel.js

@@ -15,15 +15,17 @@ var Excel =
       // set worksheet max width per col
       const colWidth = data.map(row =>
         row.map(val => {
-          var l = val.toString().length;
-          var n = l + l*0.5;
           // if null/undefined
           if (val == null) {
             return { wch: 10 };
           } else if (val.toString().charCodeAt(0) > 255) {
             // if chinese
+            var l = val.toString().length;
+            var n = l + l*0.5;
             return { wch: n * 2 };
           } else {
+            var l = val.toString().length;
+            var n = l + l*0.5;
             return { wch: n };
           }
         })