Use a hook for the ever-updating now

ts/hooks/useNowThatUpdatesEveryMinute.ts

@@ -0,0 +1,27 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { EventEmitter } from 'events';
+import { useEffect, useState } from 'react';
+
+import { MINUTE } from '../util/durations';
+
+const ev = new EventEmitter();
+setInterval(() => ev.emit('tick'), MINUTE);
+
+export function useNowThatUpdatesEveryMinute(): number {
+  const [now, setNow] = useState(Date.now());
+
+  useEffect(() => {
+    const updateNow = () => setNow(Date.now());
+    updateNow();
+
+    ev.on('tick', updateNow);
+
+    return () => {
+      ev.off('tick', updateNow);
+    };
+  }, []);
+
+  return now;
+}