Convert frontend code to typescript (#31559)

None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
61105d0618
because of a deprecation that was not showing before the rename).

`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.

Everything appears to work fine.

web_src/js/features/notification.ts

@@ -0,0 +1,193 @@
+import $ from 'jquery';
+import {GET} from '../modules/fetch.ts';
+import {toggleElem} from '../utils/dom.ts';
+import {logoutFromWorker} from '../modules/worker.ts';
+
+const {appSubUrl, notificationSettings, assetVersionEncoded} = window.config;
+let notificationSequenceNumber = 0;
+
+export function initNotificationsTable() {
+  const table = document.querySelector('#notification_table');
+  if (!table) return;
+
+  // when page restores from bfcache, delete previously clicked items
+  window.addEventListener('pageshow', (e) => {
+    if (e.persisted) { // page was restored from bfcache
+      const table = document.querySelector('#notification_table');
+      const unreadCountEl = document.querySelector('.notifications-unread-count');
+      let unreadCount = parseInt(unreadCountEl.textContent);
+      for (const item of table.querySelectorAll('.notifications-item[data-remove="true"]')) {
+        item.remove();
+        unreadCount -= 1;
+      }
+      unreadCountEl.textContent = unreadCount;
+    }
+  });
+
+  // mark clicked unread links for deletion on bfcache restore
+  for (const link of table.querySelectorAll('.notifications-item[data-status="1"] .notifications-link')) {
+    link.addEventListener('click', (e) => {
+      e.target.closest('.notifications-item').setAttribute('data-remove', 'true');
+    });
+  }
+}
+
+async function receiveUpdateCount(event) {
+  try {
+    const data = JSON.parse(event.data);
+
+    for (const count of document.querySelectorAll('.notification_count')) {
+      count.classList.toggle('tw-hidden', data.Count === 0);
+      count.textContent = `${data.Count}`;
+    }
+    await updateNotificationTable();
+  } catch (error) {
+    console.error(error, event);
+  }
+}
+
+export function initNotificationCount() {
+  if (!document.querySelector('.notification_count')) return;
+
+  let usingPeriodicPoller = false;
+  const startPeriodicPoller = (timeout, lastCount) => {
+    if (timeout <= 0 || !Number.isFinite(timeout)) return;
+    usingPeriodicPoller = true;
+    lastCount = lastCount ?? getCurrentCount();
+    setTimeout(async () => {
+      await updateNotificationCountWithCallback(startPeriodicPoller, timeout, lastCount);
+    }, timeout);
+  };
+
+  if (notificationSettings.EventSourceUpdateTime > 0 && window.EventSource && window.SharedWorker) {
+    // Try to connect to the event source via the shared worker first
+    const worker = new SharedWorker(`${__webpack_public_path__}js/eventsource.sharedworker.js?v=${assetVersionEncoded}`, 'notification-worker');
+    worker.addEventListener('error', (event) => {
+      console.error('worker error', event);
+    });
+    worker.port.addEventListener('messageerror', () => {
+      console.error('unable to deserialize message');
+    });
+    worker.port.postMessage({
+      type: 'start',
+      url: `${window.location.origin}${appSubUrl}/user/events`,
+    });
+    worker.port.addEventListener('message', (event) => {
+      if (!event.data || !event.data.type) {
+        console.error('unknown worker message event', event);
+        return;
+      }
+      if (event.data.type === 'notification-count') {
+        const _promise = receiveUpdateCount(event.data);
+      } else if (event.data.type === 'no-event-source') {
+        // browser doesn't support EventSource, falling back to periodic poller
+        if (!usingPeriodicPoller) startPeriodicPoller(notificationSettings.MinTimeout);
+      } else if (event.data.type === 'error') {
+        console.error('worker port event error', event.data);
+      } else if (event.data.type === 'logout') {
+        if (event.data.data !== 'here') {
+          return;
+        }
+        worker.port.postMessage({
+          type: 'close',
+        });
+        worker.port.close();
+        logoutFromWorker();
+      } else if (event.data.type === 'close') {
+        worker.port.postMessage({
+          type: 'close',
+        });
+        worker.port.close();
+      }
+    });
+    worker.port.addEventListener('error', (e) => {
+      console.error('worker port error', e);
+    });
+    worker.port.start();
+    window.addEventListener('beforeunload', () => {
+      worker.port.postMessage({
+        type: 'close',
+      });
+      worker.port.close();
+    });
+
+    return;
+  }
+
+  startPeriodicPoller(notificationSettings.MinTimeout);
+}
+
+function getCurrentCount() {
+  return document.querySelector('.notification_count').textContent;
+}
+
+async function updateNotificationCountWithCallback(callback, timeout, lastCount) {
+  const currentCount = getCurrentCount();
+  if (lastCount !== currentCount) {
+    callback(notificationSettings.MinTimeout, currentCount);
+    return;
+  }
+
+  const newCount = await updateNotificationCount();
+  let needsUpdate = false;
+
+  if (lastCount !== newCount) {
+    needsUpdate = true;
+    timeout = notificationSettings.MinTimeout;
+  } else if (timeout < notificationSettings.MaxTimeout) {
+    timeout += notificationSettings.TimeoutStep;
+  }
+
+  callback(timeout, newCount);
+  if (needsUpdate) {
+    await updateNotificationTable();
+  }
+}
+
+async function updateNotificationTable() {
+  const notificationDiv = document.querySelector('#notification_div');
+  if (notificationDiv) {
+    try {
+      const params = new URLSearchParams(window.location.search);
+      params.set('div-only', true);
+      params.set('sequence-number', ++notificationSequenceNumber);
+      const url = `${appSubUrl}/notifications?${params.toString()}`;
+      const response = await GET(url);
+
+      if (!response.ok) {
+        throw new Error('Failed to fetch notification table');
+      }
+
+      const data = await response.text();
+      if ($(data).data('sequence-number') === notificationSequenceNumber) {
+        notificationDiv.outerHTML = data;
+        initNotificationsTable();
+      }
+    } catch (error) {
+      console.error(error);
+    }
+  }
+}
+
+async function updateNotificationCount() {
+  try {
+    const response = await GET(`${appSubUrl}/notifications/new`);
+
+    if (!response.ok) {
+      throw new Error('Failed to fetch notification count');
+    }
+
+    const data = await response.json();
+
+    toggleElem('.notification_count', data.new !== 0);
+
+    for (const el of document.querySelectorAll('.notification_count')) {
+      el.textContent = `${data.new}`;
+    }
+
+    return `${data.new}`;
+  } catch (error) {
+    console.error(error);
+    return '0';
+  }
+}