WIP - the most basic thought-outline of one object

only committing this to create the branch and because this does
represent at least a tiny amount of time spent and I don't want it
to only be sitting on one storage device

packages/auth/lib/TotpMultiFactorGenerator.js

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2016-present Invertase Limited & Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this library except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+export default class TotpMultiFactorGenerator {
+  static FACTOR_ID = 'totp';
+
+  constructor() {
+    throw new Error(
+      '`new TotpMultiFactorGenerator()` is not supported on the native Firebase SDKs.',
+    );
+  }
+
+  // TotpSecret has a fair bit of stuff going on: https://firebase.google.com/docs/reference/js/auth.totpsecret.md#totpsecret_class
+  // static assertionForEnrollment(secret: TotpSecret, oneTimePassword: string): TotpMultiFactorAssertion {
+  //   return null;
+  // }
+
+  // TotpMultiFactorAssertion is a trivial subclass
+  // static assertionForSignIn(enrollmentId: string, oneTimePassword: string): TotpMultiFactorAssertion {
+  //   return null;
+  // }
+
+  // static generateSecret(session: MultiFactorSession): Promise<TotpSecret> {
+  //   return null;
+  // }
+
+}