Move to protobufjs in ts/groups.ts

ts/test-both/util/dropNull_test.ts

@@ -0,0 +1,19 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+import { assert } from 'chai';
+
+import { dropNull } from '../../util/dropNull';
+
+describe('dropNull', () => {
+  it('swaps null with undefined', () => {
+    assert.strictEqual(dropNull(null), undefined);
+  });
+
+  it('leaves undefined be', () => {
+    assert.strictEqual(dropNull(undefined), undefined);
+  });
+
+  it('non-null values undefined be', () => {
+    assert.strictEqual(dropNull('test'), 'test');
+  });
+});