added length to avoid error (#892)

check tabIds.length avoid error

functional-samples/tutorial.tabs-manager/popup.js

@@ -46,6 +46,8 @@ document.querySelector('ul').append(...elements);
 const button = document.querySelector('button');
 button.addEventListener('click', async () => {
   const tabIds = tabs.map(({ id }) => id);
-  const group = await chrome.tabs.group({ tabIds });
-  await chrome.tabGroups.update(group, { title: 'DOCS' });
+  if (tabIds.length) {
+    const group = await chrome.tabs.group({ tabIds });
+    await chrome.tabGroups.update(group, { title: 'DOCS' });
+  }
 });