gh-claudeforge-marketplace-plugins-commands-bundle-analyzer/commands/bundle-analyzer.md

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Bash, Read, Write, Edit, Grep, Glob	ClaudeForge bundle size analysis and optimization specialist for webpack, rollup, and modern build tools.

ClaudeForge Bundle Analyzer

ClaudeForge intelligent bundle analysis system that identifies, analyzes, and optimizes JavaScript bundle sizes with comprehensive visualization, tree shaking recommendations, and automated code splitting strategies.

Purpose

Transform bundle optimization from manual investigation to intelligent automation that ensures optimal application performance, minimal load times, and efficient code delivery across modern web applications.

Features

• Bundle Analysis: Deep analysis of webpack, rollup, and vite bundles with visual dependency graphs
• Size Optimization: Identify and eliminate bloated dependencies and unused code
• Tree Shaking: Optimize tree shaking configuration for maximum dead code elimination
• Code Splitting: Intelligent code splitting strategies for optimal chunk sizes
• Dependency Audit: Analyze dependency tree and identify duplicate or redundant packages
• Performance Metrics: Measure real-world performance impact with Web Vitals integration
• Report Generation: Comprehensive reports with actionable optimization recommendations
• CI/CD Integration: Automated bundle size monitoring in continuous integration pipelines

Usage

/bundle-analyzer [command] [options]

Target: $ARGUMENTS (if specified, otherwise analyze current build output)

Analysis Commands

Full Bundle Analysis:

/bundle-analyzer analyze --build-dir=dist --format=html

Generates comprehensive bundle analysis including:

• Visual treemap of bundle composition
• Module size breakdown by category
• Duplicate dependency detection
• Largest modules and optimization opportunities
• Import cost analysis
• Bundle size trends over time

Webpack Bundle Analysis:

/bundle-analyzer webpack --stats-file=stats.json --threshold=500kb

Analyzes webpack bundles with:

• webpack-bundle-analyzer integration
• Chunk size analysis and optimization
• Module concatenation opportunities
• Dynamic import boundary detection
• Vendor bundle optimization
• SplitChunks configuration recommendations

Source Map Explorer:

/bundle-analyzer source-map --bundle=main.js --output=report.html

Uses source-map-explorer for:

• Visual representation of bundle content
• Source file size attribution
• Library version detection
• Minification effectiveness analysis
• Gzip/Brotli compression preview

Optimization Commands

Tree Shaking Optimization:

/bundle-analyzer tree-shake --aggressive --side-effects-check

Optimizes tree shaking with:

• Side effects analysis and package.json validation
• ESM module format verification
• Import statement optimization
• Unused export detection
• Babel configuration recommendations
• Package.json sideEffects configuration

Code Splitting Strategy:

/bundle-analyzer code-split --strategy=route-based --max-chunk=250kb

Implements intelligent code splitting:

• Route-based splitting for SPA applications
• Component-level splitting with React.lazy/Vue async
• Vendor bundle separation strategies
• Common chunk extraction optimization
• Dynamic import insertion points
• Prefetch/preload directive generation

Dependency Optimization:

/bundle-analyzer dependencies --find-duplicates --suggest-alternatives

Optimizes dependency usage:

• Duplicate dependency detection and resolution
• Lighter alternative library suggestions
• Peer dependency conflict resolution
• Bundle phobia integration for size checking
• Package.json dependency audit
• Monorepo workspace optimization

Advanced Features

Performance Budget:

/bundle-analyzer budget --max-initial=500kb --max-route=250kb --fail-on-breach

Enforces performance budgets with:

• Initial bundle size limits
• Per-route chunk size constraints
• Asset size monitoring (images, fonts, etc.)
• CI/CD integration for automated checks
• Historical size tracking
• Budget breach notifications

Compression Analysis:

/bundle-analyzer compress --algorithms=gzip,brotli,zstd --level=11

Analyzes compression effectiveness:

• Multiple compression algorithm comparison
• Compression ratio analysis
• Pre-compression build plugin recommendations
• CDN compression configuration
• Content-encoding header validation

Import Cost Analysis:

/bundle-analyzer imports --annotate --threshold=50kb

Provides import-level insights:

• Per-import size calculation
• Named vs default import optimization
• Import statement annotations in source
• Barrel export detection and optimization
• Module replacement recommendations

Analysis Methodologies

Bundle Size Metrics

Core Web Vitals Impact:

• First Contentful Paint (FCP): Initial bundle load time impact
• Largest Contentful Paint (LCP): Critical resource optimization
• Time to Interactive (TTI): JavaScript parse and execution cost
• Total Blocking Time (TBT): Main thread blocking analysis
• Cumulative Layout Shift (CLS): Dynamic import layout impact

Size Categories:

• Initial Bundle: Critical path JavaScript for first render
• Route Chunks: Lazy-loaded route-specific code
• Vendor Bundles: Third-party library code
• Shared Chunks: Common code across multiple routes
• Async Chunks: Dynamically imported modules

Optimization Strategies

Tree Shaking Excellence:

// Bad: CommonJS imports prevent tree shaking
const _ = require('lodash');
const cloneDeep = _.cloneDeep;

// Good: ESM named imports enable tree shaking
import { cloneDeep } from 'lodash-es';

// Best: Direct function imports minimize bundle size
import cloneDeep from 'lodash-es/cloneDeep';

Code Splitting Patterns:

// Route-based splitting
const Dashboard = lazy(() => import('./pages/Dashboard'));
const Profile = lazy(() => import('./pages/Profile'));

// Component-based splitting with prefetch
const HeavyChart = lazy(() => import(
  /* webpackChunkName: "chart" */
  /* webpackPrefetch: true */
  './components/HeavyChart'
));

// Dynamic import with error boundary
const loadModule = () => import('./module').catch(err => {
  console.error('Module load failed:', err);
  return { default: FallbackComponent };
});

Webpack Configuration Optimization:

// Optimal SplitChunks configuration
optimization: {
  splitChunks: {
    chunks: 'all',
    cacheGroups: {
      vendor: {
        test: /[\\/]node_modules[\\/]/,
        name(module) {
          const packageName = module.context.match(
            /[\\/]node_modules[\\/](.*?)([\\/]|$)/
          )[1];
          return `vendor.${packageName.replace('@', '')}`;
        },
        priority: 10
      },
      common: {
        minChunks: 2,
        priority: 5,
        reuseExistingChunk: true,
        enforce: true
      }
    }
  },
  runtimeChunk: 'single',
  moduleIds: 'deterministic'
}

Tool Integration

Webpack Bundle Analyzer

Installation and Setup:

npm install --save-dev webpack-bundle-analyzer

Configuration:

const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin;

module.exports = {
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'static',
      reportFilename: 'bundle-report.html',
      openAnalyzer: false,
      generateStatsFile: true,
      statsFilename: 'bundle-stats.json'
    })
  ]
};

Source Map Explorer

Analysis Workflow:

# Generate source maps
npm run build -- --source-map

# Analyze main bundle
npx source-map-explorer dist/main.*.js --html dist/sme-report.html

# Compare bundles
npx source-map-explorer dist/*.js --only-mapped

Bundle Phobia Integration

Dependency Size Checking:

# Check package size before installation
npx bundle-phobia moment

# Compare alternatives
npx bundle-phobia moment date-fns dayjs

# Size impact analysis
npx bundle-phobia --interactive

Performance Optimization Techniques

Dependency Management

Library Alternatives:

• moment.js (67KB) → date-fns (13KB) or dayjs (2KB)
• lodash (71KB) → lodash-es (24KB) with tree shaking
• axios (13KB) → native fetch with polyfill (0KB modern browsers)
• jquery (87KB) → vanilla JS or cash (6KB)
• core-js (90KB) → targeted polyfills with browserslist

Tree Shaking Optimization:

{
  "sideEffects": [
    "*.css",
    "*.scss",
    "./src/polyfills.js"
  ]
}

Build Tool Configuration

Vite Optimization:

// vite.config.js
export default {
  build: {
    rollupOptions: {
      output: {
        manualChunks: {
          'react-vendor': ['react', 'react-dom'],
          'ui-vendor': ['@mui/material', '@mui/icons-material'],
          'utils': ['lodash-es', 'date-fns']
        }
      }
    },
    chunkSizeWarningLimit: 500,
    minify: 'terser',
    terserOptions: {
      compress: {
        drop_console: true,
        drop_debugger: true
      }
    }
  }
};

Rollup Optimization:

// rollup.config.js
export default {
  plugins: [
    terser({
      compress: {
        passes: 2,
        pure_getters: true,
        unsafe: true
      },
      mangle: {
        safari10: true
      }
    }),
    visualizer({
      filename: 'bundle-analysis.html',
      gzipSize: true,
      brotliSize: true
    })
  ]
};

CI/CD Integration

GitHub Actions Workflow

name: Bundle Size Check

on: [pull_request]

jobs:
  bundle-size:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3

      - name: Install dependencies
        run: npm ci

      - name: Build and analyze
        run: npm run build

      - name: Analyze bundle size
        uses: andresz1/size-limit-action@v1
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          limit: "500 KB"

      - name: Comment PR with bundle report
        uses: marocchino/sticky-pull-request-comment@v2
        with:
          path: bundle-report.md

Size Limit Configuration

{
  "size-limit": [
    {
      "name": "Initial Bundle",
      "path": "dist/main.*.js",
      "limit": "500 KB",
      "gzip": true
    },
    {
      "name": "Total App Size",
      "path": "dist/**/*.js",
      "limit": "1.5 MB",
      "gzip": true
    }
  ]
}

Reporting and Visualization

HTML Report Generation

Comprehensive Analysis Report:

• Bundle composition treemap visualization
• Size breakdown by module category
• Dependency graph with version information
• Optimization recommendations ranked by impact
• Historical size trend charts
• Compression effectiveness analysis

Command Line Output

Summary Statistics:

Bundle Analysis Summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Total Bundle Size: 1.2 MB (489 KB gzipped)
Initial Load: 456 KB (189 KB gzipped)
Lazy Chunks: 744 KB (300 KB gzipped)

Top 5 Largest Modules:
1. node_modules/react-dom/cjs/react-dom.production.min.js - 120 KB
2. node_modules/@mui/material/esm/index.js - 87 KB
3. node_modules/recharts/es6/index.js - 65 KB
4. src/pages/Dashboard/index.js - 43 KB
5. node_modules/date-fns/esm/index.js - 38 KB

Optimization Opportunities:
• Replace moment.js with date-fns (saves 54 KB)
• Enable aggressive tree shaking (potential 120 KB reduction)
• Split vendor bundle into smaller chunks
• Consider dynamic imports for Dashboard (43 KB)

Performance Budget Status: ⚠️  WARNING
Initial bundle exceeds recommended 400 KB limit

JSON Export

Programmatic Analysis:

{
  "bundles": [
    {
      "name": "main",
      "size": 456000,
      "gzipSize": 189000,
      "modules": 342,
      "duplicates": 3
    }
  ],
  "recommendations": [
    {
      "type": "dependency-replacement",
      "module": "moment",
      "suggestion": "date-fns",
      "savings": 54000
    }
  ]
}

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ClaudeForge Bundle Analyzer - Intelligent bundle size optimization with comprehensive analysis, actionable recommendations, and automated performance monitoring.