Fixing JS exceptions on profiles page (#9904)

Author: advay26

src/NuGetGallery/Scripts/gallery/page-list-packages.js

@@ -48,42 +48,49 @@ $(function() {
         collapsible.addEventListener('click', toggleCollapsible);
     }
 
-    const advancedSearchToggleButton = document.getElementById('advancedSearchToggleButton');
-    advancedSearchToggleButton.addEventListener('click', toggleAdvancedSearchPanel);
     var resized = false;
     var initialScreenSize = window.innerWidth;
     const chevronIcon = document.getElementById('advancedSearchToggleChevron');
 
+    const advancedSearchToggleButton = document.getElementById('advancedSearchToggleButton');
+
+    if (advancedSearchToggleButton) {
+        advancedSearchToggleButton.addEventListener('click', toggleAdvancedSearchPanel);
+    }
+
+    window.addEventListener('resize', () => {
+        resized = true;
+        toggleAdvancedSearchPanel();
+    });
+
     /* For narrow screens only */
     function toggleAdvancedSearchPanel() {
 
         const filtersContent = document.getElementById('advancedSearchPanel');
-        var computedStyle = window.getComputedStyle(filtersContent);
 
-        if (window.innerWidth <= 992 && !resized) {
-            filtersContent.style.display = (computedStyle.display === 'none') ? 'block' : 'none';
-            chevronIcon.classList.toggle('ms-Icon--ChevronDown');
-            chevronIcon.classList.toggle('ms-Icon--ChevronUp');
-        }
-        else if (window.innerWidth <= 992 && initialScreenSize > 992 && resized) {
-            filtersContent.style.display = 'none';
-            chevronIcon.classList.add('ms-Icon--ChevronDown');
-            chevronIcon.classList.remove('ms-Icon--ChevronUp');
+        if (filtersContent) {
+            var computedStyle = window.getComputedStyle(filtersContent);
 
-        }
-        else if (window.innerWidth > 992) {
-            filtersContent.style.display = 'block';
+            if (window.innerWidth <= 992 && !resized) {
+                filtersContent.style.display = (computedStyle.display === 'none') ? 'block' : 'none';
+                chevronIcon.classList.toggle('ms-Icon--ChevronDown');
+                chevronIcon.classList.toggle('ms-Icon--ChevronUp');
+            }
+            else if (window.innerWidth <= 992 && initialScreenSize > 992 && resized) {
+                filtersContent.style.display = 'none';
+                chevronIcon.classList.add('ms-Icon--ChevronDown');
+                chevronIcon.classList.remove('ms-Icon--ChevronUp');
+
+            }
+            else if (window.innerWidth > 992) {
+                filtersContent.style.display = 'block';
+            }
         }
 
         initialScreenSize = window.innerWidth;
         resized = false;
     }
 
-    window.addEventListener('resize', () => {
-        resized = true;
-        toggleAdvancedSearchPanel(); 
-    });
-
     function toggleCollapsible() {
         var dataTab = document.getElementById(this.getAttribute('tab') + 'tab');
         var expandButton = document.getElementById(this.getAttribute('tab') + 'button');