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Sivasubramaniyam
Sivasubramaniyam

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Tracking the Very First User Interaction in Next.js — Cross-Tab, Auto-Reset, and SPA-Safe

#webdev #nextjs #react #datalayer

Modern web apps often load analytics or performance scripts on page load — but the real engagement starts only when the user actually interacts.

That’s where the First User Interaction Tracker helps. It detects the very first click or pointer event across all tabs, prevents duplicates,and resets automatically when the browser closes.

Project Overview

Project Name: First User Interaction

Purpose:

Track and synchronize the very first user engagement across browser tabs — ideal for analytics, performance optimization, and user experience metrics.

Features

Feature Description
Global tracking Tracks the very first click or pointer interaction in any tab.
Cross-tab sync Shares the interaction state instantly across all open tabs using BroadcastChannel.
Auto-reset When all browser tabs/windows are closed, the session clears automatically (sessionStorage).
No duplicates Prevents multiple 🎉 First user interaction captured logs when opening new tabs or navigating.
Path awareness Logs which route (pathname) the event occurred on.
SPA-safe Works across Next.js client-side navigations without retriggering.

🧾 Output Example 


[InteractionListener] 🎉 First user interaction captured at 2025-10-16 06:52:03 on path: /
[InteractionListener] First interaction captured in another tab (live). Path: /saunas
[InteractionListener] First interaction already captured in this tab/session. Path: /about
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Why This Matters

This tracker is great for developers who want to:

  • Measure Time to First Interaction (TTFI) — a true user engagement metric.
  • Defer heavy scripts until real user action (improving performance).
  • Start cookie consent or analytics logic only after voluntary interaction.
  • Maintain cross-tab session state without backend dependency.
  • Get precise behavior in Next.js client-side routing.

Ideal Use Cases

Use Case Example
Analytics Trigger Google Tag Manager or Segment events only after interaction.
Performance Lazy-load third-party scripts post engagement.
Compliance Activate cookie consent logic only after user action.
UX Metrics Measure user engagement timing accurately.
Multi-tab coordination Prevent duplicate “session start” events across tabs.

Tech Stack

  • Next.js 14 (App Router)
  • React 18
  • BroadcastChannel API
  • sessionStorage

Demo Setup

  1. Clone the project:

    bash
    git clone https://github.com/Sivamani-18/First-User-Interaction.git
    cd First-User-Interaction
    npm install
    npm run dev
    `

  2. Open multiple tabs:

  • http://localhost:3000
  • http://localhost:3000/about
  • http://localhost:3000/contact
  1. Open DevTools → Console, then click anywhere once — 🎉 You’ll see only one “First user interaction captured” log per browser session.

Author

Sivamaniyam (Sivamani)
Frontend Lead · React / Next.js · Accessibility & Performance Advocate

🔗 GitHub
🌐 Website
💼 LinkedIn

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