Ensure globals.js is loaded prior to execution of dependent scripts

This commit prevents a race condition that causes global variables
defined in globals.js to be inaccessible to the other content scripts

globals.js

@@ -1,5 +1,8 @@
+if (typeof window.globalsLoaded === 'undefined') {
     console.log('globals.js loaded');
 
+    window.globalsLoaded = true;
+
     let lastChecked = null;
 
     let Selectors = {
@@ -14,3 +17,10 @@ let Selectors = {
     };
 
     let CHECKBOX_CLASS = 'conversation-checkbox';
+
+    window.lastChecked = lastChecked;
+    window.Selectors = Selectors;
+    window.CHECKBOX_CLASS = CHECKBOX_CLASS;
+} else {
+    console.log('globals.js already loaded, skipping re-initialization');
+}

popup.js

@@ -1,43 +1,37 @@
-document.getElementById('add-checkboxes').addEventListener('click', () => {
-  chrome.tabs.query({ active: true, currentWindow: true }, ([tab]) => {
+function loadGlobalsThenExecute(tabId, secondaryScript) {
   chrome.scripting.executeScript({
-      target: { tabId: tab.id },
-      files: ['addCheckboxes.js']
-    });
-  });
-});
-
-document.getElementById('bulk-delete').addEventListener('click', () => {
-  chrome.tabs.query({ active: true, currentWindow: true }, ([tab]) => {
+    target: { tabId: tabId },
+    files: ['globals.js']
+  }, () => {
     chrome.scripting.executeScript({
-      target: { tabId: tab.id },
-      files: ['bulkDeleteConversations.js']
-    });
+      target: { tabId: tabId },
+      files: [secondaryScript]
     });
   });
+}
 
-document.getElementById('toggle-checkboxes').addEventListener('click', () => {
+function addButtonListener(buttonId, scriptName) {
+  document.getElementById(buttonId).addEventListener('click', () => {
     chrome.tabs.query({ active: true, currentWindow: true }, ([tab]) => {
-    chrome.scripting.executeScript({
-      target: { tabId: tab.id },
-      files: ['toggleCheckboxes.js']
-    });
+      if (tab) {
+        loadGlobalsThenExecute(tab.id, scriptName);
+      }
     });
   });
+}
 
-document.getElementById('remove-checkboxes').addEventListener('click', () => {
-  chrome.tabs.query({ active: true, currentWindow: true }, ([tab]) => {
-    chrome.scripting.executeScript({
-      target: { tabId: tab.id },
-      files: ['removeCheckboxes.js']
-    });
-  });
-});
+function initializeButtons() {
+  addButtonListener('add-checkboxes', 'addCheckboxes.js');
+  addButtonListener('bulk-delete', 'bulkDeleteConversations.js');
+  addButtonListener('toggle-checkboxes', 'toggleCheckboxes.js');
+  addButtonListener('remove-checkboxes', 'removeCheckboxes.js');
+}
 
-
-// Update copyright year
+function updateCopyrightYear() {
   const currentYear = new Date().getFullYear();
   document.getElementById('copyright').innerHTML =
-  '&copy; ' + currentYear + ' <a href="https://github.com/qcrao/bulk-delete-chatGPT" target="_blank">qcrao@GitHub</a>';
-
+    `&copy; ${currentYear} <a href="https://github.com/qcrao/bulk-delete-chatGPT" target="_blank">qcrao@GitHub</a>`;
+}
 
+initializeButtons();
+updateCopyrightYear();