fix: generating a UUID for anonymousID initial value, refactor userId replacement (#440)

Author: oscb

packages/core/src/analytics.ts

@@ -491,7 +491,7 @@ export class SegmentClient {
 
     this.store.userInfo.set({
       ...userInfo,
-      ...(userId !== undefined ? { userId } : {}),
+      userId: userId ?? userInfo.userId,
       traits: mergedTraits,
     });
 

packages/core/src/storage/sovranStorage.ts

@@ -7,6 +7,7 @@ import type {
   Context,
   UserInfoState,
 } from '..';
+import { getUUID } from '../uuid';
 import type { Storage } from './types';
 
 type Data = {
@@ -24,7 +25,7 @@ const INITIAL_VALUES: Data = {
   context: {},
   settings: {},
   userInfo: {
-    anonymousId: 'anonymousId',
+    anonymousId: getUUID(),
     userId: undefined,
     traits: undefined,
   },