Refactor code structure for improved readability and maintainability

Fuchs/wwwroot/web/fis.inv.de.js

@@ -1509,7 +1509,6 @@ $inv.sprev = (change) => {
     }
     $ocms.postXT({
         url: $ocms.url('req/' + (change === true ?'sedit':'sprep')), data: { invc: JSON.stringify($inv.invcPayload(d)), id: d.invid ||'' }, success: (response) => {
-            l.rC('freeze');
             let c = $$.dc('imagecollection pdfpreview'), vhr = Math.round(vh() * 0.88), invid = response.id, invtp = response.total;
             if (invtp > 10) {
                 $$.dc('note warn', c).text($ict.tpe);
@@ -1523,15 +1522,20 @@ $inv.sprev = (change) => {
             $ocms.dlg(c, {
                 size: [vhr, Math.round(vw() * 0.88)], zindex: 50, form: false, button: $rct.crI, confirm: function (e) {
                     let ct = $(this);
+                    l.aC('freeze');  /* spinner while the invoice is finalized/emailed on the backend */
                     $ocms.postXT({
-                        url: $ocms.url('req/sconf'), data: { id: invid }, success: () => {
+                        url: $ocms.url('req/sconf'), data: { id: invid }, success: (cresp) => {
                             ct.trigger('modal_close');
-                            window.open($ocms.url('req/idoc') + '?id=' + invid, '_blank');  /* open pdf in new tab */
+                            if (cresp.hasFile === true) {
+                                window.open($ocms.url('req/idoc') + '?id=' + invid, '_blank');  /* open pdf in new tab, only if a file was actually created */
+                            }
                             $ocms.init('req');   /* go back to request list */
                             $inv.rReload();
                         }, error: () => {
                             alert($t.f1);
                             ct.trigger('modal_close');
+                        }, complete: () => {
+                            l.rC('freeze');
                         }
                     });
                 }, cancel: function (e) {
@@ -1546,6 +1550,10 @@ $inv.sprev = (change) => {
                     $inv.rReload();
                 }
             });
+        }, error: () => {
+            alert($ict.eis);
+        }, complete: () => {
+            l.rC('freeze');
         }
     });
 };