Fix: include initial stable id in web analytics (#412)

* fix: include initial stable id in web analytics

* chore: linter

* chore: set user

* chore: fix accidental default value

* chore: edit fn name

packages/combo/src/__tests__/WebAnalyticsInitialStableID.test.ts

@@ -0,0 +1,56 @@
+import fetchMock from 'jest-fetch-mock';
+
+import { StatsigClient, StatsigUser } from '@statsig/js-client';
+import {
+  StatsigAutoCapturePlugin,
+  runStatsigAutoCapture,
+} from '@statsig/web-analytics';
+
+describe('Plugin Stable ID Override Tests', () => {
+  let client: StatsigClient;
+  const user: StatsigUser = {
+    userID: 'a-user',
+    customIDs: {
+      stableID: 'a-stable-id',
+    },
+  };
+  beforeAll(() => {
+    fetchMock.enableMocks();
+  });
+
+  afterAll(async () => {
+    await client.shutdown();
+    fetchMock.mockClear();
+  });
+
+  it('Run auto capture includes initial user stable Id', async () => {
+    client = new StatsigClient('client-key', user);
+    runStatsigAutoCapture(client);
+    await client.initializeAsync();
+
+    const request = fetchMock.mock.calls[1];
+    const body = JSON.parse(String(request[1]?.body ?? '')) as any;
+    expect(body.events).toHaveLength(1);
+
+    const event = body.events[0];
+    expect(event.eventName).toEqual('auto_capture::page_view');
+    expect(event.user?.customIDs?.stableID).toEqual('a-stable-id');
+    expect(body?.statsigMetadata?.stableID).toEqual('a-stable-id');
+  });
+
+  it('Auto capture plugin includes initial user stable Id', async () => {
+    client = new StatsigClient('client-key', user, {
+      plugins: [new StatsigAutoCapturePlugin()],
+    });
+    await client.initializeAsync();
+
+    const request = fetchMock.mock.calls[1];
+    const body = JSON.parse(String(request[1]?.body ?? '')) as any;
+    expect(body.events).toHaveLength(1);
+
+    const event = body.events[0];
+    expect(event.eventName).toEqual('auto_capture::page_view');
+    expect(event.user?.customIDs?.stableID).toEqual('a-stable-id');
+    expect(body?.statsigMetadata?.stableID).toEqual('a-stable-id');
+  });
+});

packages/js-client/src/StatsigClient.ts

@@ -101,7 +101,7 @@ export default class StatsigClient
     );
 
     this._store = new EvaluationStore(sdkKey);
-    this._user = _normalizeUser(user, options);
+    this._user = this._configureUser(user, options);
 
     const plugins = options?.plugins ?? [];
     for (const plugin of plugins) {
@@ -370,12 +370,19 @@ export default class StatsigClient
     this._logger.reset();
     this._store.reset();
 
-    this._user = _normalizeUser(user, this._options);
+    this._user = this._configureUser(user, this._options);
+  }
 
-    const stableIdOverride = this._user.customIDs?.stableID;
+  private _configureUser(
+    originalUser: StatsigUser,
+    options: StatsigOptions | null,
+  ): StatsigUserInternal {
+    const user = _normalizeUser(originalUser, options);
+    const stableIdOverride = user.customIDs?.stableID;
     if (stableIdOverride) {
       StableID.setOverride(stableIdOverride, this._sdkKey);
     }
+    return user;
   }
 
   private _getFeatureGateImpl(