refactor: fix identify argument type and tests (#436)

* refactor: fix identify argument type and tests

* refactor: fix test to account for traits object updates

Co-authored-by: Alan Charles <[email protected]>

Author: alanjcharles

packages/core/src/__tests__/methods/identify.test.ts

@@ -79,4 +79,27 @@ describe('methods #identify', () => {
       userId: 'new-user-id',
     });
   });
+
+  it('does not update userId when userId is undefined', () => {
+    const client = new SegmentClient(clientArgs);
+    jest.spyOn(client, 'process');
+
+    client.identify(undefined, { name: 'Mary' });
+
+    const expectedEvent = {
+      traits: { name: 'Mary', age: 30 },
+      userId: undefined,
+      type: 'identify',
+    };
+
+    expect(client.process).toHaveBeenCalledTimes(1);
+    expect(client.process).toHaveBeenCalledWith(expectedEvent);
+    expect(client.userInfo.get()).toEqual({
+      ...initialUserInfo,
+      traits: {
+        age: 30,
+        name: 'Mary',
+      },
+    });
+  });
 });

packages/core/src/analytics.ts

@@ -475,7 +475,7 @@ export class SegmentClient {
     this.logger.info('TRACK event saved', event);
   }
 
-  identify(userId: string, userTraits?: UserTraits) {
+  identify(userId?: string, userTraits?: UserTraits) {
     const userInfo = this.store.userInfo.get();
     const { traits: currentUserTraits } = userInfo;
 
@@ -491,7 +491,7 @@ export class SegmentClient {
 
     this.store.userInfo.set({
       ...userInfo,
-      userId: userId,
+      ...(userId !== undefined ? { userId } : {}),
       traits: mergedTraits,
     });