Convert app loading message code to TypeScript

ts/background.ts

@@ -39,6 +39,7 @@ import { assert, strictAssert } from './util/assert';
 import { normalizeUuid } from './util/normalizeUuid';
 import { filter } from './util/iterables';
 import { isNotNil } from './util/isNotNil';
+import { setAppLoadingScreenMessage } from './setAppLoadingScreenMessage';
 import { IdleDetector } from './IdleDetector';
 import { expiringMessagesDeletionService } from './services/expiringMessagesDeletion';
 import { tapToViewMessagesDeletionService } from './services/tapToViewMessagesDeletionService';
@@ -502,7 +503,6 @@ export async function startApp(): Promise<void> {
     deleteAttachmentData,
     doesAttachmentExist,
   } = window.Signal.Migrations;
-  const { Views } = window.Signal;
 
   log.info('background page reloaded');
   log.info('environment:', window.getEnvironment());
@@ -546,7 +546,10 @@ export async function startApp(): Promise<void> {
     return accountManager;
   };
 
-  const cancelInitializationMessage = Views.Initialization.setMessage();
+  const cancelInitializationMessage = setAppLoadingScreenMessage(
+    undefined,
+    window.i18n
+  );
 
   const version = await window.Signal.Data.getItemById('version');
   if (!version) {
@@ -792,7 +795,10 @@ export async function startApp(): Promise<void> {
       }
     }
 
-    Views.Initialization.setMessage(window.i18n('optimizingApplication'));
+    setAppLoadingScreenMessage(
+      window.i18n('optimizingApplication'),
+      window.i18n
+    );
 
     if (newVersion) {
       // We've received reports that this update can take longer than two minutes, so we
@@ -816,7 +822,7 @@ export async function startApp(): Promise<void> {
       log.error('SQL failed to initialize', err && err.stack ? err.stack : err);
     }
 
-    Views.Initialization.setMessage(window.i18n('loading'));
+    setAppLoadingScreenMessage(window.i18n('loading'), window.i18n);
 
     let isMigrationWithIndexComplete = false;
     log.info(

ts/setAppLoadingScreenMessage.ts

@@ -0,0 +1,47 @@
+// Copyright 2018-2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { LocalizerType } from './types/Util';
+
+const DISPLAY_THRESHOLD = 3000; // milliseconds
+const SELECTOR = '.app-loading-screen .message';
+
+let timeout: null | ReturnType<typeof setTimeout>;
+let targetString: string;
+let didTimeout = false;
+
+const clear = () => {
+  if (timeout) {
+    clearTimeout(timeout);
+    timeout = null;
+  }
+};
+
+export function setAppLoadingScreenMessage(
+  loadingText: undefined | string,
+  i18n: LocalizerType
+): () => void {
+  const message = document.querySelector<HTMLElement>(SELECTOR);
+  if (!message) {
+    return clear;
+  }
+
+  targetString = loadingText || i18n('optimizingApplication');
+
+  message.innerText = didTimeout ? targetString : i18n('loading');
+
+  if (timeout) {
+    return clear;
+  }
+
+  timeout = setTimeout(() => {
+    didTimeout = true;
+    const innerMessage = document.querySelector<HTMLElement>(SELECTOR);
+    if (!innerMessage) {
+      return;
+    }
+    innerMessage.innerText = targetString;
+  }, DISPLAY_THRESHOLD);
+
+  return clear;
+}

ts/window.d.ts

@@ -383,7 +383,6 @@ declare global {
         WhatsNewLink: typeof WhatsNewLink;
       };
       OS: typeof OS;
-      Views: WhatIsThis;
       State: {
         createStore: typeof createStore;
         Roots: {