fix: sessionId for first open and session start events

src/tracker/Session.ts

@@ -51,25 +51,29 @@ export class Session {
 		this.pauseTime = new Date().getTime();
 	}
 
-	static getCurrentSession(context: ClickstreamContext): Session {
-		const storedSession = StorageUtil.getSession();
-		let sessionIndex = 1;
-		if (storedSession !== null) {
+	static getCurrentSession(
+		context: ClickstreamContext,
+		previousSession: Session = null
+	): Session {
+		let session = previousSession;
+		if (previousSession === null) {
+			session = StorageUtil.getSession();
+		}
+		if (session !== null) {
 			if (
-				new Date().getTime() - storedSession.pauseTime <
+				new Date().getTime() - session.pauseTime <
 				context.configuration.sessionTimeoutDuration
 			) {
-				return new Session(
-					storedSession.sessionId,
-					storedSession.sessionIndex,
-					storedSession.startTime,
-					storedSession.pauseTime
-				);
+				return session;
 			} else {
-				sessionIndex = storedSession.sessionIndex + 1;
+				return Session.createSession(
+					context.userUniqueId,
+					session.sessionIndex + 1
+				);
 			}
+		} else {
+			return Session.createSession(context.userUniqueId, 1);
 		}
-		return Session.createSession(context.userUniqueId, sessionIndex);
 	}
 
 	private static getSessionId(uniqueId: string): string {

src/tracker/SessionTracker.ts

@@ -65,7 +65,9 @@ export class SessionTracker extends BaseTracker {
 		logger.debug('page appear');
 		const pageViewTracker = this.provider.pageViewTracker;
 		pageViewTracker.updateLastScreenStartTimestamp();
-		this.session = Session.getCurrentSession(this.context);
+		if (!isFirstTime) {
+			this.session = Session.getCurrentSession(this.context, this.session);
+		}
 		if (this.session.isNewSession()) {
 			pageViewTracker.setIsEntrances();
 			StorageUtil.clearPageInfo();

src/util/StorageUtil.ts

@@ -255,7 +255,13 @@ export class StorageUtil {
 		if (sessionStr === null) {
 			return null;
 		}
-		return JSON.parse(sessionStr) as Session;
+		const sessionObject = JSON.parse(sessionStr);
+		return new Session(
+			sessionObject.sessionId,
+			sessionObject.sessionIndex,
+			sessionObject.startTime,
+			sessionObject.pauseTime
+		);
 	}
 
 	static getIsFirstOpen(): boolean {

test/tracker/SessionTracker.test.ts

@@ -27,7 +27,7 @@ import {
 	Event,
 	EventRecorder,
 } from '../../src/provider';
-import { PageViewTracker, SessionTracker } from '../../src/tracker';
+import { PageViewTracker, SessionTracker, Session } from '../../src/tracker';
 import { StorageUtil } from '../../src/util/StorageUtil';
 import { setPerformanceEntries } from '../browser/BrowserUtil';
 import { MockObserver } from '../browser/MockObserver';
@@ -96,6 +96,16 @@ describe('SessionTracker test', () => {
 		expect(session.isNewSession()).toBeTruthy();
 	});
 
+	test('test first open and session start event has the same sessionId', () => {
+		sessionTracker.setUp();
+		const allEvents = JSON.parse(StorageUtil.getAllEvents() + ']');
+		const firstOpenEvent = allEvents[0];
+		const sessionStartEvent = allEvents[1];
+		expect(
+			firstOpenEvent.sessionId === sessionStartEvent.sessionId
+		).toBeTruthy();
+	});
+
 	test('test enable app start', () => {
 		provider.configuration.isTrackAppStartEvents = true;
 		sessionTracker.setUp();
@@ -235,6 +245,18 @@ describe('SessionTracker test', () => {
 		expect(trackPageViewMock).toBeCalled();
 	});
 
+	test('test launch the app use the stored session', () => {
+		const session = Session.createSession(context.userUniqueId, 2);
+		session.pauseTime = new Date().getTime() - 1100;
+		StorageUtil.saveSession(session);
+		sessionTracker.setUp();
+		expect(sessionTracker.session.startTime).toBe(session.startTime);
+		expect(sessionTracker.session.sessionId).toBe(session.sessionId);
+		expect(sessionTracker.session.sessionIndex).toBe(session.sessionIndex);
+		expect(sessionTracker.session.pauseTime > 1000).toBeTruthy();
+		expect(sessionTracker.session.isNewSession()).toBeFalsy();
+	});
+
 	test('test send event in batch mode when hide page', async () => {
 		const sendEventBackgroundMock = jest.spyOn(
 			eventRecorder,