typing status: Lengthen the hardcoded expiry period to 45s

src/typing/typingActions.js

@@ -4,6 +4,33 @@ import type { PerAccountAction, ThunkAction } from '../types';
 import { sleep } from '../utils/async';
 import { getTyping } from '../directSelectors';
 
+/**
+ * The value to use for `server_typing_started_expiry_period_milliseconds`.
+ *
+ * The corresponding old server setting was `TYPING_STARTED_EXPIRY_PERIOD`.
+ *
+ * The specified behavior is that we should be taking this value from server
+ * data.  See docs:
+ *   https://chat.zulip.org/api/set-typing-status
+ *
+ * But in this legacy codebase, the most expedient thing is to hardcode it
+ * to a large value.  We'll get proper user-facing behavior as long as this
+ * value exceeds by at least a network round-trip the effective value of
+ * `server_typing_started_wait_period_milliseconds` in the behavior of other
+ * clients.  Discussion:
+ *   https://chat.zulip.org/#narrow/stream/243-mobile-team/topic/typing.20notifications.20constants/near/1665193
+ */
+const typingStartedExpiryPeriodMs = 45000;
+
+/**
+ * The period at which to poll for expired typing notifications.
+ *
+ * Really no polling should be needed here -- a timer would be better.
+ * But that's how this code has always worked, and for this legacy codebase
+ * that'll do.
+ */
+const typingPollPeriodMs = 3000;
+
 export const clearTyping = (outdatedNotifications: $ReadOnlyArray<string>): PerAccountAction => ({
   type: 'CLEAR_TYPING',
   outdatedNotifications,
@@ -12,15 +39,15 @@ export const clearTyping = (outdatedNotifications: $ReadOnlyArray<string>): PerA
 const typingStatusExpiryLoop = () => async (dispatch, getState) => {
   // loop to auto dismiss typing notifications after typingNotificationTimeout
   while (true) {
-    await sleep(15000);
+    await sleep(typingPollPeriodMs);
     const currentTime = new Date().getTime();
     const typing = getTyping(getState());
     if (Object.keys(typing).length === 0) {
       break; // break if no typing notifications
     }
     const outdatedNotifications = [];
     Object.keys(typing).forEach(recipients => {
-      if (currentTime - typing[recipients].time >= 15000) {
+      if (currentTime - typing[recipients].time >= typingStartedExpiryPeriodMs) {
         outdatedNotifications.push(recipients);
       }
     });