Feat/posthog analytics

[aman-wednesdaysol]

PostHog Analytics Integration

Description

This PR introduces backend analytics tracking using PostHog across authentication and music library flows.

A centralized analytics layer was added to provide consistent, non-blocking event tracking while keeping business logic isolated from analytics concerns. Tracking is implemented using fire-and-forget helpers to avoid impacting request latency.

Key Features

• Singleton PostHog client with graceful shutdown support
• Centralized event definitions
• Lightweight tracking helpers
• Analytics automatically disabled/mocked during tests
• Coverage added across auth and music interactions

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Implementation Details

New Files

lib/analytics/client.js

• Initializes PostHog singleton client
• Exposes shutdownAnalytics() for graceful process termination

lib/analytics/events.js

• Centralized analytics event name constants

lib/analytics/tracker.js

• Fire-and-forget tracking helpers
• Prevents analytics failures from affecting API responses

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Modified Files

Infrastructure

• webpack/server.config.js — Added @analytics alias

• jest.config.json — Added analytics module mapping

• jest.setup.js — Mocked analytics during tests

• .env.local — Added:

  • POSTHOG_API_KEY
  • POSTHOG_HOST

Server Lifecycle

• server.js — Added SIGINT handler invoking shutdownAnalytics() to flush queued events before shutdown

Tracked Routes

• lib/routes/login/routes.js → trackLogin

• lib/routes/signup/routes.js → trackSignup

• lib/routes/logout/routes.js → trackLogout

• lib/routes/music/resources/routes.js → trackSongSearched

• lib/routes/music/library/routes.js

  • trackLibraryViewed
  • trackSongLiked
  • trackSongUnliked

Tests

• lib/routes/signup/tests/routes.test.js

  • Updated mock data shape to include required user property

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Results

• ✅ Application builds successfully
• ✅ Analytics runs asynchronously without affecting request flow
• ✅ Graceful shutdown ensures event delivery
• ✅ All existing tests remain stable
• ✅ 115/115 tests passing

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Steps to Reproduce / Test

1. Add analytics environment variables:

POSTHOG_API_KEY=<your_key>
POSTHOG_HOST=<host_url>

2. Start the server:

yarn start

3. Perform the following actions:

   • Sign up
   • Log in / log out
   • Search for songs
   • View library
   • Like / unlike a song

4. Verify events appear in PostHog dashboard.

5. Run tests:

yarn test

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Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)

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Project	Deployment	Actions	Updated (UTC)
nodejs-hapi-template	Error		Feb 25, 2026 9:35am