Hide "become a sustainer" button if you're already a sustainer

ts/services/areWeASubscriber.ts

@@ -0,0 +1,36 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { StorageInterface } from '../types/Storage.d';
+import type { WebAPIType } from '../textsecure/WebAPI';
+import { LatestQueue } from '../util/LatestQueue';
+import { waitForOnline } from '../util/waitForOnline';
+
+// This is only exported for testing.
+export class AreWeASubscriberService {
+  private readonly queue = new LatestQueue();
+
+  update(
+    storage: Pick<StorageInterface, 'get' | 'put' | 'onready'>,
+    server: Pick<WebAPIType, 'getHasSubscription'>
+  ): void {
+    this.queue.add(async () => {
+      await new Promise<void>(resolve => storage.onready(resolve));
+
+      const subscriberId = storage.get('subscriberId');
+      if (!subscriberId || !subscriberId.byteLength) {
+        storage.put('areWeASubscriber', false);
+        return;
+      }
+
+      await waitForOnline(navigator, window);
+
+      storage.put(
+        'areWeASubscriber',
+        await server.getHasSubscription(subscriberId)
+      );
+    });
+  }
+}
+
+export const areWeASubscriberService = new AreWeASubscriberService();