[5.x] Update nocache map on response (#11650)

Co-authored-by: Jason Varga <jason@pixelfear.com>

Author: indykoning

src/StaticCaching/Cachers/FileCacher.php

@@ -207,13 +207,18 @@ public function getNocacheJs(): string
 
         $default = <<<EOT
 (function() {
-    var els = document.getElementsByClassName('nocache');
-    var map = {};
-    for (var i = 0; i < els.length; i++) {
-        var section = els[i].getAttribute('data-nocache');
-        map[section] = els[i];
+    function createMap() {
+        var map = {};
+        var els = document.getElementsByClassName('nocache');
+        for (var i = 0; i < els.length; i++) {
+            var section = els[i].getAttribute('data-nocache');
+            map[section] = els[i];
+        }
+        return map;
     }
 
+    var map = createMap();
+
     fetch('/!/nocache', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
@@ -224,6 +229,8 @@ public function getNocacheJs(): string
     })
     .then((response) => response.json())
     .then((data) => {
+        map = createMap(); // Recreate map in case the DOM changed.
+
         const regions = data.regions;
         for (var key in regions) {
             if (map[key]) map[key].outerHTML = regions[key];