fix: indicator doesn't update after mask as read (#154)

Author: tjx666

source/github-notifications-preview.css

@@ -206,3 +206,7 @@
 #AppHeader-notifications-button {
 	z-index: 81;
 }
+
+#AppHeader-notifications-button > svg::before {
+	display: var(--notifications-icon-indicator-display, "block");
+  }

source/github-notifications-preview.jsx

@@ -59,10 +59,18 @@ function isOpen(element) {
 	return elementExists('.NPG-container[open], .NPG-loading', element);
 }
 
+function updateNotificationsIndicatorStatus(show) {
+	$('#AppHeader-notifications-button > svg').style.setProperty(
+		'--notifications-icon-indicator-display',
+		show ? 'block' : 'none',
+	);
+}
+
 async function updateUnreadCount() {
 	const latestStatusElement = $('.notification-indicator .mail-status', await notifications.dom);
-	const latestCount = $('.js-notification-inboxes .selected .count', await notifications.dom).textContent;
+	const latestCount = $('.js-notification-inboxes .selected .count', await notifications.dom)?.textContent ?? '';
 	const rghCount = getRefinedGitHubUnreadCount();
+	updateNotificationsIndicatorStatus(latestCount && (Number(latestCount) + rghCount > 0));
 
 	for (const statusElement of $$('.notification-indicator .mail-status')) {
 		if (options.previewCount && statusElement.textContent !== latestCount) {