v0.4.0

Next.js 16 Migration

Complete update of all skills and prompts for Next.js 16

Cache Components & "use cache" Directive

• Breaking: Route segment configs deprecated with cacheComponents
• New "use cache" directive for file, component, and function-level caching
• cacheLife() for cache duration: 'seconds', 'minutes', 'hours', 'days', 'weeks', 'max'
• cacheTag() and updateTag() for granular cache invalidation

Async Dynamic APIs (Breaking Change)

• All dynamic APIs must now be awaited: params, searchParams, cookies(), headers(), draftMode()

Turbopack (Default Bundler)

• Turbopack is now the default bundler in Next.js 16
• Context detector now returns turbopack as build tool for Next.js 16+

React 19.2 Features

• React Compiler for automatic memoization
• View Transitions for smooth page transitions
• Activity component for preserved state

Image Optimization

• Default minimumCacheTTL changed to 4 hours
• Default quality coerced to [75]
• dangerouslyAllowLocalIP required for localhost

Breaking Changes

• Node.js 20.9+ is now required by Next.js 16 projects
• Skills and prompts now target Next.js 16 patterns by default

v0.3.1

Added

• CLI --version flag - Show package version with perf-check --version or -V

Changed

• Renamed src/.github to src/templates - Clearer naming for distributable prompts and skills
• Next.js 15 performance best practices - Updated all skills and prompts with latest recommendations:
  • New after() API for deferred tasks
  • Partial prerendering patterns
  • Turbopack production considerations
  • Server Actions optimization
  • Cache control improvements

v0.3.0

[0.3.0] - 2026-02-03

Added

• Export Pattern Analyzer (#13) - Analyze module exports for tree-shaking optimization

  • ExportAnalyzer class for detecting suboptimal export patterns
  • analyzeExports() convenience function for quick analysis
  • --audit-exports CLI flag for command-line analysis
  • Detects default exports, barrel files, namespace re-exports
  • next.config.js analysis for optimizePackageImports configuration
  • Actionable recommendations with code examples and estimated impact
  • New subpath export: @silverassist/performance-toolkit/analyzer
  • New Copilot skill: nextjs-tree-shaking for AI-assisted optimization
  • New Copilot prompt: audit-exports.prompt.md for guided analysis

• Bundle Analyzer Integration (#9) - Integration with @next/bundle-analyzer

  • BundleAnalyzerRunner class with fluent builder pattern
  • createBundleAnalyzer() factory function
  • analyzeBundle() convenience function
  • perf-bundle CLI command for standalone bundle analysis
  • Chunk analysis with size tracking and dependency detection
  • Support for both client and server bundle analysis
  • New subpath export: @silverassist/performance-toolkit/bundle

• GTM/GA Optimization Skill (#11) - Copilot skill for Google Tag Manager optimization

  • New skill: gtm-optimization with validated dynamic import patterns
  • Best practices for GTM/GA4 integration in Next.js
  • Performance-focused loading strategies

Fixed

• ReDoS vulnerabilities in export analyzer regex patterns
  • Replaced vulnerable nested quantifiers with bounded character classes
  • Uses [^}]{1,1000} pattern to prevent catastrophic backtracking

v0.2.1

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog,
and this project adheres to Semantic Versioning.

[0.2.1] - 2026-02-01

Added

• Expanded test coverage - Increased from 27.77% to 95.58% statements, 9.58% to 80.82% branches
  • Added comprehensive tests for report/ module (utils, diagnostics, lcp, opportunities, generator)
  • Added tests for context/ module with mocked filesystem
  • Added tests for pagespeed/utils.ts and pagespeed/insights.ts
  • Total: 242 tests across 10 test suites

Changed

• Improved prompt installer (bin/install-prompts.js) - Major overhaul for better VS Code integration
  • Install prompts at root level (.github/prompts/) for proper VS Code recognition
  • Added manifest tracking (.perf-toolkit-manifest.json) to safely manage installed files
  • Safe directory names to protect user files from accidental overwrites
  • Prefixed prompt files with performance/ namespace for organization

Fixed

• Type errors in test files - Fixed MetricValue interface usage (removed non-existent score property)
• AuditDetails type compliance - Added required type field to mock audit details
• ProjectContext completeness - Added missing buildTool property in test fixtures
• Prompt partial references - Fixed relative paths in nextjs-performance.prompt.md and optimize-lcp.prompt.md

[0.2.0] - 2026-02-01

Changed

Module Refactoring (DDD Pattern)

• Refactored src/pagespeed/ module - Split monolithic 814-line file into 6 focused modules:

  • constants.ts - API URLs, timeouts, audit IDs, third-party patterns
  • utils.ts - Formatting helpers (cache TTL, URL truncation, entity extraction)
  • extractors.ts - Score, metric, LCP, opportunity, diagnostic extractors
  • insights.ts - Detailed insights for AI agents (cache, images, JS, third-parties)
  • client.ts - PageSpeedClient class and factory functions
  • index.ts - Barrel exports for public API

• Refactored src/report/ module - Split monolithic 959-line file into 6 focused modules:

  • utils.ts - Formatting and severity calculation helpers
  • diagnostics.ts - Diagnostics table generation
  • lcp.ts - LCP analysis and recommendations
  • opportunities.ts - Key opportunities with framework-specific guidance
  • generator.ts - ActionableReportGenerator class
  • index.ts - Barrel exports for public API

• Refactored bin/cli.js - Applied DRY principles to 1350+ line CLI:

  • Added global constants for colors/emojis (SEVERITY_, IMPACT_, STATUS_, URGENCY_)
  • Added helper functions: getSeverityStyle(), getImpactStyle(), getStatusStyle()
  • Added print helpers: printSectionHeader(), printSectionFooter(), printLabeledValue(), etc.
  • Refactored all major print functions to use shared helpers

JSDoc Header Standardization

• Standardized file headers across all TypeScript files (24 files updated):
  • Replaced @packageDocumentation with standard JSDoc tags
  • Added @module following DDD path structure (e.g., pagespeed/client)
  • Added @author with email
  • Added @license PolyForm-Noncommercial-1.0.0
  • Added @see link to repository (main entry point only)
  • Documented standards in .github/copilot-instructions.md

Types Refactoring (DDD Pattern)

• Reorganized src/types/ folder following Domain-Driven Design pattern with barrel exports
• Split monolithic 967-line index.ts into 8 domain-specific modules:
  • metrics/ - Core Web Vitals, MetricValue, CategoryScores
  • pagespeed/ - PageSpeed API types (Strategy, Category, Options, Response, CrUX, Lighthouse)
  • lighthouse/ - LHCI types (Method, Options, Assertions, Config)
  • analysis/ - Results, diagnostics, opportunities, LCP elements, insights
  • context/ - ProjectContext, FrameworkInfo
  • report/ - ActionableReport, KeyOpportunity, NextStep
  • cli/ - CLIOptions, CLIResult, ThresholdViolation
  • config/ - PerformanceThresholds, ProjectConfig, ToolkitConfig
• Main index.ts now re-exports all domains using export type {} pattern
• Backward compatible - existing imports continue to work

Project Organization

• Moved distributable Copilot prompts and skills from .github/ to src/.github/
  • Separates repository config from installable content
  • Updated bin/install-prompts.js paths
  • Updated package.json files array
• Updated copilot-instructions.md with current architecture documentation

[0.1.0] - 2026-01-30

Added

Core Features

• PageSpeed Insights API Client - Full integration with Google PageSpeed Insights API v5
  • PageSpeedClient class for multiple analyses
  • analyzeUrl() function for quick single-URL analysis
  • Support for mobile/desktop strategies
  • All four categories: Performance, Accessibility, Best Practices, SEO

Metrics Extraction

• Core Web Vitals - LCP, FCP, CLS, TBT, Speed Index, TTI
• LCP Element Detection - Identify the largest contentful paint element
• Opportunities - Performance improvement suggestions with estimated savings
• Diagnostics - Detailed diagnostic information

Detailed Insights for AI Agents

• LCP Timing Breakdown - TTFB, resource load delay, load duration, render delay
• Third-Party Impact Analysis - Blocking time and transfer size per vendor with category classification
• Unused JavaScript Tracking - Wasted bytes with first-party/third-party attribution
• Unused CSS Analysis - Stylesheets with coverage percentage
• Cache Policy Issues - Resources with poor or missing cache headers
• Image Optimization - Format, sizing, offscreen, and compression issues
• Legacy JavaScript Detection - Polyfills that can be removed
• Render-Blocking Resources - Scripts/styles delaying first paint
• Long Tasks Detection - Main-thread blocking tasks with URL attribution
• Total Savings Summary - Aggregate time and size savings

Lighthouse CI Integration

• LighthouseRunner class for programmatic LHCI execution
• Two execution methods:
  • node - Local Chrome for staging/internal URLs
  • psi - PageSpeed API for production URLs
• Assertion configuration for CI/CD pipelines
• Upload targets: temporary-public-storage, LHCI server, filesystem

CLI Tool

• perf-check command for command-line analysis
• Mobile/desktop strategy options
• Verbose mode with opportunities display
• --insights / -i flag - Show detailed insights in terminal format
• --json / -j flag - Output structured JSON for programmatic use
• CI mode with threshold validation
• JSON output support

Utilities

• getDefaultThresholds() - Standard and strict threshold presets
• createNodeRunner() - Quick setup for staging analysis
• createPSIRunner() - Quick setup for production analysis
• createHybridRunners() - Combined staging + production setup

TypeScript

• Complete type definitions for all APIs
• Exported types for external use
• Strict type checking

Security

• API key support for higher rate limits
• No credentials stored in package

---

Initial Release for SilverAssist performance monitoring.

v0.2.0

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog,
and this project adheres to Semantic Versioning.

[0.2.0] - 2026-02-01

Changed

Module Refactoring (DDD Pattern)

• Refactored src/pagespeed/ module - Split monolithic 814-line file into 6 focused modules:

  • constants.ts - API URLs, timeouts, audit IDs, third-party patterns
  • utils.ts - Formatting helpers (cache TTL, URL truncation, entity extraction)
  • extractors.ts - Score, metric, LCP, opportunity, diagnostic extractors
  • insights.ts - Detailed insights for AI agents (cache, images, JS, third-parties)
  • client.ts - PageSpeedClient class and factory functions
  • index.ts - Barrel exports for public API

• Refactored src/report/ module - Split monolithic 959-line file into 6 focused modules:

  • utils.ts - Formatting and severity calculation helpers
  • diagnostics.ts - Diagnostics table generation
  • lcp.ts - LCP analysis and recommendations
  • opportunities.ts - Key opportunities with framework-specific guidance
  • generator.ts - ActionableReportGenerator class
  • index.ts - Barrel exports for public API

• Refactored bin/cli.js - Applied DRY principles to 1350+ line CLI:

  • Added global constants for colors/emojis (SEVERITY_, IMPACT_, STATUS_, URGENCY_)
  • Added helper functions: getSeverityStyle(), getImpactStyle(), getStatusStyle()
  • Added print helpers: printSectionHeader(), printSectionFooter(), printLabeledValue(), etc.
  • Refactored all major print functions to use shared helpers

JSDoc Header Standardization

• Standardized file headers across all TypeScript files (24 files updated):
  • Replaced @packageDocumentation with standard JSDoc tags
  • Added @module following DDD path structure (e.g., pagespeed/client)
  • Added @author with email
  • Added @license PolyForm-Noncommercial-1.0.0
  • Added @see link to repository (main entry point only)
  • Documented standards in .github/copilot-instructions.md

Types Refactoring (DDD Pattern)

• Reorganized src/types/ folder following Domain-Driven Design pattern with barrel exports
• Split monolithic 967-line index.ts into 8 domain-specific modules:
  • metrics/ - Core Web Vitals, MetricValue, CategoryScores
  • pagespeed/ - PageSpeed API types (Strategy, Category, Options, Response, CrUX, Lighthouse)
  • lighthouse/ - LHCI types (Method, Options, Assertions, Config)
  • analysis/ - Results, diagnostics, opportunities, LCP elements, insights
  • context/ - ProjectContext, FrameworkInfo
  • report/ - ActionableReport, KeyOpportunity, NextStep
  • cli/ - CLIOptions, CLIResult, ThresholdViolation
  • config/ - PerformanceThresholds, ProjectConfig, ToolkitConfig
• Main index.ts now re-exports all domains using export type {} pattern
• Backward compatible - existing imports continue to work

Project Organization

• Moved distributable Copilot prompts and skills from .github/ to src/.github/
  • Separates repository config from installable content
  • Updated bin/install-prompts.js paths
  • Updated package.json files array
• Updated copilot-instructions.md with current architecture documentation

[0.1.0] - 2026-01-30

Added

Core Features

• PageSpeed Insights API Client - Full integration with Google PageSpeed Insights API v5
  • PageSpeedClient class for multiple analyses
  • analyzeUrl() function for quick single-URL analysis
  • Support for mobile/desktop strategies
  • All four categories: Performance, Accessibility, Best Practices, SEO

Metrics Extraction

• Core Web Vitals - LCP, FCP, CLS, TBT, Speed Index, TTI
• LCP Element Detection - Identify the largest contentful paint element
• Opportunities - Performance improvement suggestions with estimated savings
• Diagnostics - Detailed diagnostic information

Detailed Insights for AI Agents

• LCP Timing Breakdown - TTFB, resource load delay, load duration, render delay
• Third-Party Impact Analysis - Blocking time and transfer size per vendor with category classification
• Unused JavaScript Tracking - Wasted bytes with first-party/third-party attribution
• Unused CSS Analysis - Stylesheets with coverage percentage
• Cache Policy Issues - Resources with poor or missing cache headers
• Image Optimization - Format, sizing, offscreen, and compression issues
• Legacy JavaScript Detection - Polyfills that can be removed
• Render-Blocking Resources - Scripts/styles delaying first paint
• Long Tasks Detection - Main-thread blocking tasks with URL attribution
• Total Savings Summary - Aggregate time and size savings

Lighthouse CI Integration

• LighthouseRunner class for programmatic LHCI execution
• Two execution methods:
  • node - Local Chrome for staging/internal URLs
  • psi - PageSpeed API for production URLs
• Assertion configuration for CI/CD pipelines
• Upload targets: temporary-public-storage, LHCI server, filesystem

CLI Tool

• perf-check command for command-line analysis
• Mobile/desktop strategy options
• Verbose mode with opportunities display
• --insights / -i flag - Show detailed insights in terminal format
• --json / -j flag - Output structured JSON for programmatic use
• CI mode with threshold validation
• JSON output support

Utilities

• getDefaultThresholds() - Standard and strict threshold presets
• createNodeRunner() - Quick setup for staging analysis
• createPSIRunner() - Quick setup for production analysis
• createHybridRunners() - Combined staging + production setup

TypeScript

• Complete type definitions for all APIs
• Exported types for external use
• Strict type checking

Security

• API key support for higher rate limits
• No credentials stored in package

---

Initial Release for SilverAssist performance monitoring.

v0.1.0 - Initial Release

🎉 Initial Release

Features

• CLI Tool: perf-check command for analyzing Core Web Vitals
• PageSpeed Insights Integration: Analyze LCP, FCP, CLS, TBT metrics
• Lighthouse CI Integration: Run Lighthouse audits programmatically
• Detailed Recommendations: Actionable optimization suggestions
• TypeScript Support: Full type definitions included

Installation

npm install @silverassist/performance-toolkit

Usage

npx perf-check https://example.com

Links

• Documentation
• npm package