browser-sw-specialist

version	1.0.0
description	Advanced technical knowledge for Service Worker runtime control and multi-tab state synchronization in the browser
name	browser-sw-specialist

Skill: Browser Service Worker & State Synchronization

Specialized technical knowledge for ensuring network interception availability (Service Worker) in the browser environment and synchronizing state in real time across multiple tabs and processes.

1. Core Competencies

• SW Lifecycle Management: Optimizing Service Worker installation (Install), activation (Activate), updates, and client control (Claim).
• Cross-Tab State Sync: Designing multi-tab state synchronization architectures using BroadcastChannel and Storage Event.
• Worker-Main Communication: High-speed data exchange and control between the main thread and background workers via postMessage and MessageChannel.
• Cache Strategy: Establishing intelligent caching/invalidation strategies for network request results and static assets.

2. Reference & Detailed Specs

• Communication Sync: Cross-Tab and Cross-Worker Synchronization Strategy
• Service Worker Debugging: Worker Anomaly Diagnosis Guide (TBD)

3. Decision Tree / Standard Workflow

• Q1. State from a previous tab is not reflected in a new tab?
  • Action: Check the BroadcastChannel message handler registration status and verify that the channel name matches.
• Q2. After a Service Worker update, existing tabs lose control?
  • Action: Inspect the timing of self.skipWaiting() and clients.claim() calls, and review the service worker lifecycle handling.
• Q3. Network request interception inside the worker is failing?
  • Action: Verify the scope of the fetch event handler and check the conditions for calling respondWith().

4. Engineering Constraints & Mandates

• "All communication logic must be implemented asynchronously to prevent main thread performance degradation; apply debouncing when necessary."
• "Communication channels between tabs must be clearly separated by purpose, and sensitive information transmitted must be minimized for security."
• "Service Worker state changes must always be observable, and logging must be performed when key events occur."