Add "new conversation" composer for direct messages

ts/test-both/util/deconstructLookup_test.ts

@@ -0,0 +1,19 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import { deconstructLookup } from '../../util/deconstructLookup';
+
+describe('deconstructLookup', () => {
+  it('looks up an array of properties in a lookup', () => {
+    const lookup = {
+      high: 5,
+      seven: 89,
+      big: 999,
+    };
+    const keys = ['seven', 'high'];
+
+    assert.deepEqual(deconstructLookup(lookup, keys), [89, 5]);
+  });
+});