YCS-Continued

Source-based development repository. Main branch: v2-source

Installation

Download the extension from official stores:

• Chrome Web Store: https://chromewebstore.google.com/detail/mfobjniokjbcldieppimekoibpocahed
• Firefox Add-ons: https://addons.mozilla.org/zh-TW/firefox/addon/ycs-continued/

Project Background

This repository is the source-based continuation of YCS (YouTube Comment Search) extension.

Status:

• Main development branch: v2-source
• Supported browsers: Chrome 88+ (Manifest V3), Firefox
• Original project: sonigy/YCS
• Migrated from ycs_cont_migration branch to single-repo structure

The extension enables searching, filtering, and exporting YouTube comments, replies, chat replays, and video transcripts, with continuous fixes for YouTube API changes (2024-2025).

Development Setup

Prerequisites

• Node.js 22+ (defined in app/.nvmrc)
• npm

Installation & Build

All development commands run from the app/ directory:

# Install dependencies
cd app
npm ci

# Development build (watch mode, HMR disabled)
npm run dev

# Production build → app/dist/
npm run build

# Clean cache and rebuild
npm run rebuild

# Lint check
npm run lint

# Type checking
npm run typecheck

# Format code with Prettier
npm run format
npm run format:check

# Clean all build artifacts
npm run rm

# Run tests with Node.js test runner
npm test

Load Extension in Browser

1. Build the extension: cd app && npm run build
2. Open browser extension page:
   • Chrome: chrome://extensions
   • Firefox: about:debugging#/runtime/this-firefox
3. Enable "Developer mode"
4. Click "Load unpacked" and select app/dist/ directory

Release Workflow

From project root, use the Makefile:

make release TYPE=patch   # Auto bump, commit, tag, build, package
make release TYPE=minor
make release TYPE=major

This will:

• Update version in app/manifest.json and app/manifest.firefox.json
• Create git commit and tag
• Build both Chrome and Firefox versions
• Package as .zip files in packing/ directory

Manual build (if needed):

./scripts/build-extension.sh chrome    # or firefox
./scripts/package-extension.sh chrome  # or firefox

Technical Documentation

Architecture Overview

Three-layer communication model:

YouTube.com Page
  ├─ web-resources.ts (Web Page Layer)
  │  └─ Search logic, UI rendering, Fuse.js integration
  │  └─ window.postMessage() ↕️
  ├─ content-scripts.ts (Content Script Layer)
  │  └─ Message relay, script injection management
  │  └─ chrome.runtime.sendMessage() ↕️
  └─ background.ts (Service Worker)
     └─ IndexedDB cache, storage monitoring, badge updates
     └─ YouTube Data API requests (API key stored securely)

Why this structure? Manifest V3 security restrictions require web page code to run in isolated context. The content script acts as a secure bridge between web page and extension background. For YouTube Data API integration, API keys are stored securely in the background and never exposed to the web page.

Build system: Parcel 2.0.1 with TypeScript (ES6 target, strict mode)

Storage: IndexedDB cache with auto-cleanup (200 MB quota limit, configurable in options)

YouTube Innertube API Integration

The extension integrates with YouTube's internal Innertube API for comments, chat replays, and transcripts.

Documentation:

• innertube-comments-integration.md - Start here for comment integration
• innertube-migration-guide.md - frameworkUpdates migration guide
• innertube-nested-comments.md - Nested replies architecture and Entity-driven format
• innertube-chat-replay-api-changes.md - Chat replay API changes
• continuation-processing.md - Implementation reference
• sap-sid-authorization.md - SAPISID authorization header generation
• adaptive-authorization-headers.md - Adaptive authorization for member-only videos
• youtube-data-api-messaging.md - YouTube Data API v3 messaging architecture

Credits

• Original YCS by sonigy
• YCS-Continued maintained by pc035860