Discriminator in username

ts/state/util.ts

@@ -0,0 +1,27 @@
+// Copyright 2022 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+export type PromiseAction<Type extends string, Payload = void, Meta = void> =
+  | ({
+      type: Type;
+      payload: Promise<Payload>;
+    } & (Meta extends void
+      ? { meta?: void }
+      : {
+          meta: Meta;
+        }))
+  | {
+      type: `${Type}_PENDING`;
+      meta: Meta;
+    }
+  | {
+      type: `${Type}_FULFILLED`;
+      payload: Payload;
+      meta: Meta;
+    }
+  | {
+      type: `${Type}_REJECTED`;
+      error: true;
+      payload: Error;
+      meta: Meta;
+    };