Extract IIFE into separate function

js/modules/debug.js

@@ -91,7 +91,11 @@ const createRandomMessage = ({ conversationId } = {}) => {
     type,
   };
 
-  const message = (() => {
+  const message = _createMessage({ commonProperties, conversationId, type });
+  return Message.initializeSchemaVersion(message);
+};
+
+const _createMessage = ({ commonProperties, conversationId, type } = {}) => {
   switch (type) {
     case 'incoming':
       return Object.assign({}, commonProperties, {
@@ -111,9 +115,6 @@ const createRandomMessage = ({ conversationId } = {}) => {
     default:
       throw new TypeError(`Unknown message type: '${type}'`);
   }
-  })();
-
-  return Message.initializeSchemaVersion(message);
 };
 
 const MEGA_BYTE = 1e6;