stack-performance/analyzers/ApplicationPerformanceAnalyzer.js

A comprehensive application stack analyzer that evaluates MEAN, MERN, and other Node.js-based applications across 15 performance criteria

const BaseAnalyzer = require('./BaseAnalyzer');

/**
 * Analyzes Application Performance based on multiple algorithmic factors
 * Not random - uses concrete metrics and patterns
 */
class ApplicationPerformanceAnalyzer extends BaseAnalyzer {
  constructor(stackInfo, projectPath) {
    super(stackInfo, projectPath, 'Application Performance');
  }

  async analyze() {
    const factors = [];

    // Factor 1: Framework Performance Characteristics (30% weight)
    const frameworkScore = this.analyzeFrameworkPerformance();
    factors.push({ score: frameworkScore, weight: 0.3 });

    // Factor 2: Code Structure and Patterns (25% weight)
    const codeStructureScore = await this.analyzeCodeStructure();
    factors.push({ score: codeStructureScore, weight: 0.25 });

    // Factor 3: Database Integration Efficiency (20% weight)
    const dbScore = await this.analyzeDatabaseIntegration();
    factors.push({ score: dbScore, weight: 0.2 });

    // Factor 4: Asset and Resource Management (15% weight)
    const assetScore = await this.analyzeAssetManagement();
    factors.push({ score: assetScore, weight: 0.15 });

    // Factor 5: Caching Implementation (10% weight)
    const cachingScore = await this.analyzeCaching();
    factors.push({ score: cachingScore, weight: 0.1 });

    const finalScore = this.calculateWeightedScore(factors);

    const details = {
      frameworkPerformance: frameworkScore,
      codeStructure: codeStructureScore,
      databaseIntegration: dbScore,
      assetManagement: assetScore,
      caching: cachingScore,
      stackType: this.stackInfo.type,
      optimizationOpportunities: this.getOptimizationOpportunities(factors)
    };

    const recommendations = this.generateRecommendations(factors);

    return this.createResult(finalScore, details, recommendations);
  }

  /**
   * Analyze framework performance characteristics
   * @returns {number} Performance score based on framework choice
   */
  analyzeFrameworkPerformance() {
    const { type, technologies } = this.stackInfo;
    let score = 70; // Base score

    // Framework-specific performance characteristics
    if (technologies.includes('Express.js')) {
      score += 15; // Express is performant and lightweight
    }
    
    if (technologies.includes('Fastify')) {
      score += 20; // Fastify is highly optimized for performance
    }
    
    if (technologies.includes('Koa')) {
      score += 12; // Koa is lightweight but slightly less ecosystem
    }

    // Frontend framework impact
    if (technologies.includes('React')) {
      score += 10; // Good performance with proper optimization
      if (this.hasDependency('react-dom')) {
        score += 5; // Server-side rendering capability
      }
    }
    
    if (technologies.includes('Angular')) {
      score += 8; // Good but heavier than React
    }
    
    if (technologies.includes('Vue.js')) {
      score += 12; // Excellent performance characteristics
    }

    // Performance-oriented dependencies
    if (this.hasDependency('compression')) score += 3;
    if (this.hasDependency('helmet')) score += 2;
    if (this.hasDependency('cors')) score += 1;

    return Math.min(100, score);
  }

  /**
   * Analyze code structure for performance patterns
   * @returns {number} Score based on code structure analysis
   */
  async analyzeCodeStructure() {
    let score = 60; // Base score
    
    // Find JavaScript/TypeScript files
    const codeFiles = this.findFiles('**/*.{js,ts,jsx,tsx}');
    
    if (codeFiles.length === 0) {
      return 50; // No code files found
    }

    // Analyze code complexity
    const complexity = await this.analyzeCodeComplexity(codeFiles);
    
    // Score based on complexity metrics
    if (complexity.avgLinesPerFile < 100) {
      score += 15; // Good file size management
    } else if (complexity.avgLinesPerFile > 500) {
      score -= 10; // Large files may indicate poor structure
    }

    if (complexity.complexityScore < 5) {
      score += 10; // Low complexity is good
    } else if (complexity.complexityScore > 20) {
      score -= 15; // High complexity affects performance
    }

    // Check for performance anti-patterns
    const antiPatternDeductions = await this.checkPerformanceAntiPatterns(codeFiles);
    score -= antiPatternDeductions;

    // Check for performance optimization patterns
    const optimizationBonus = await this.checkOptimizationPatterns(codeFiles);
    score += optimizationBonus;

    return Math.max(0, Math.min(100, score));
  }

  /**
   * Check for performance anti-patterns in code
   * @param {Array<string>} files - Code files to analyze
   * @returns {number} Deduction points for anti-patterns
   */
  async checkPerformanceAntiPatterns(files) {
    let deductions = 0;
    
    for (const file of files.slice(0, 20)) { // Limit to first 20 files for performance
      const content = await this.readFile(file);
      if (!content) continue;

      // Synchronous operations in Node.js
      if (content.includes('readFileSync') || content.includes('writeFileSync')) {
        deductions += 5;
      }

      // Inefficient loops
      if (content.match(/for\s*\([^)]*\.length[^)]*\)/g)) {
        deductions += 3;
      }

      // Memory leaks patterns
      if (content.includes('setInterval') && !content.includes('clearInterval')) {
        deductions += 4;
      }

      // Blocking operations
      if (content.includes('process.exit') || content.includes('while(true)')) {
        deductions += 8;
      }
    }

    return Math.min(30, deductions); // Cap at 30 points
  }

  /**
   * Check for performance optimization patterns
   * @param {Array<string>} files - Code files to analyze
   * @returns {number} Bonus points for optimizations
   */
  async checkOptimizationPatterns(files) {
    let bonus = 0;
    
    for (const file of files.slice(0, 20)) {
      const content = await this.readFile(file);
      if (!content) continue;

      // Async/await usage (modern, performant)
      if (content.includes('async') && content.includes('await')) {
        bonus += 3;
      }

      // Promise usage
      if (content.includes('Promise')) {
        bonus += 2;
      }

      // Efficient array methods
      if (content.includes('.map(') || content.includes('.filter(') || content.includes('.reduce(')) {
        bonus += 2;
      }

      // Error handling
      if (content.includes('try') && content.includes('catch')) {
        bonus += 1;
      }
    }

    return Math.min(15, bonus); // Cap at 15 points
  }

  /**
   * Analyze database integration efficiency
   * @returns {number} Database integration score
   */
  async analyzeDatabaseIntegration() {
    let score = 70; // Base score

    if (this.hasDependency('mongoose')) {
      score += 15; // Good MongoDB integration
      
      // Check for connection pooling
      const configFiles = this.findFiles('**/config/**/*.{js,ts,json}');
      for (const file of configFiles) {
        const content = await this.readFile(file);
        if (content && content.includes('maxPoolSize')) {
          score += 5;
          break;
        }
      }
    }

    if (this.hasDependency('mongodb')) {
      score += 12; // Native MongoDB driver
    }

    // Check for query optimization patterns
    const modelFiles = this.findFiles('**/models/**/*.{js,ts}');
    for (const file of modelFiles) {
      const content = await this.readFile(file);
      if (content) {
        if (content.includes('index') || content.includes('Index')) {
          score += 3; // Database indexing
        }
        if (content.includes('populate')) {
          score += 2; // Efficient data population
        }
      }
    }

    return Math.min(100, score);
  }

  /**
   * Analyze asset and resource management
   * @returns {number} Asset management score
   */
  async analyzeAssetManagement() {
    let score = 60; // Base score

    // Check for build tools
    if (this.hasDependency('webpack')) {
      score += 15;
      
      // Check for webpack optimization config
      if (await this.fileExists('webpack.config.js')) {
        const config = await this.readFile('webpack.config.js');
        if (config && config.includes('optimization')) {
          score += 10;
        }
      }
    }

    if (this.hasDependency('vite')) {
      score += 18; // Vite is highly optimized
    }

    if (this.hasDependency('parcel')) {
      score += 12;
    }

    // Check for minification
    if (this.hasDependency('terser') || this.hasDependency('uglify-js')) {
      score += 8;
    }

    // Check for CSS optimization
    if (this.hasDependency('css-loader') || this.hasDependency('mini-css-extract-plugin')) {
      score += 5;
    }

    return Math.min(100, score);
  }

  /**
   * Analyze caching implementation
   * @returns {number} Caching score
   */
  async analyzeCaching() {
    let score = 50; // Base score

    // Server-side caching
    if (this.hasDependency('redis')) {
      score += 20;
    }

    if (this.hasDependency('memcached')) {
      score += 15;
    }

    if (this.hasDependency('node-cache')) {
      score += 10;
    }

    // HTTP caching headers
    const serverFiles = this.findFiles('**/server.{js,ts}');
    const appFiles = this.findFiles('**/app.{js,ts}');
    const routeFiles = this.findFiles('**/routes/**/*.{js,ts}');
    
    const allServerFiles = [...serverFiles, ...appFiles, ...routeFiles];
    
    for (const file of allServerFiles) {
      const content = await this.readFile(file);
      if (content) {
        if (content.includes('Cache-Control') || content.includes('ETag')) {
          score += 10;
          break;
        }
      }
    }

    return Math.min(100, score);
  }

  /**
   * Get optimization opportunities based on analysis
   * @param {Array<Object>} factors - Analysis factors
   * @returns {Array<string>} List of opportunities
   */
  getOptimizationOpportunities(factors) {
    const opportunities = [];
    
    factors.forEach(factor => {
      if (factor.score < 70) {
        switch (factors.indexOf(factor)) {
          case 0: opportunities.push('Framework optimization needed'); break;
          case 1: opportunities.push('Code structure improvements required'); break;
          case 2: opportunities.push('Database queries can be optimized'); break;
          case 3: opportunities.push('Asset bundling and minification needed'); break;
          case 4: opportunities.push('Caching strategy implementation required'); break;
        }
      }
    });

    return opportunities;
  }

  /**
   * Generate performance improvement recommendations
   * @param {Array<Object>} factors - Analysis factors
   * @returns {Array<string>} Recommendations
   */
  generateRecommendations(factors) {
    const recommendations = [];
    
    if (factors[0].score < 80) {
      recommendations.push('Consider using a more performant framework like Fastify for better throughput');
    }
    
    if (factors[1].score < 70) {
      recommendations.push('Refactor large files and reduce code complexity for better performance');
    }
    
    if (factors[2].score < 75) {
      recommendations.push('Implement database connection pooling and query optimization');
    }
    
    if (factors[3].score < 70) {
      recommendations.push('Set up proper build optimization with webpack or vite');
    }
    
    if (factors[4].score < 60) {
      recommendations.push('Implement Redis or in-memory caching for frequently accessed data');
    }

    return recommendations;
  }
}

module.exports = ApplicationPerformanceAnalyzer;