handle startup errors

Signed-off-by: Vladimir Mandic <mandic00@live.com>

javascript/changelog.js

@@ -60,6 +60,10 @@ function changelogNavigate(found) {
 async function initChangelog() {
   const search = gradioApp().querySelector('#changelog_search > label> textarea');
   const md = gradioApp().getElementById('changelog_markdown');
+  if (!search || !md) {
+    error('initChangelog', 'Missing search or markdown elements');
+    return;
+  }
   const searchChangelog = async (e) => {
     if (changelogElements.length < 100) changelogElements = getAllChildren(md);
     const found = [];

javascript/gallery.js

@@ -469,6 +469,10 @@ async function initGallery() { // triggered on gradio change to monitor when ui
   el.files = gradioApp().getElementById('tab-gallery-files');
   el.status = gradioApp().getElementById('tab-gallery-status');
   el.search = gradioApp().querySelector('#tab-gallery-search textarea');
+  if (!el.folders || !el.files || !el.status || !el.search) {
+    error('initGallery', 'Missing gallery elements');
+    return;
+  }
   el.search.addEventListener('input', gallerySearch);
   el.btnSend = gradioApp().getElementById('tab-gallery-send-image');
   document.getElementById('tab-gallery-files').style.height = opts.logmonitor_show ? '75vh' : '85vh';

javascript/settings.js

@@ -181,6 +181,10 @@ async function initSettings() {
   if (settingsInitialized) return;
   settingsInitialized = true;
   const tabNavElements = gradioApp().querySelector('#settings > .tab-nav');
+  if (!tabNavElements) {
+    error('initSettings', 'No tab nav elements found');
+    return;
+  }
   const tabNavButtons = gradioApp().querySelectorAll('#settings > .tab-nav > button');
   const tabElements = gradioApp().querySelectorAll('#settings > div:not(.tab-nav)');
   const observer = new MutationObserver((mutations) => {