agentsqripts/lib/scalability/nPlusOneDetector.js

Comprehensive static code analysis toolkit for identifying technical debt, security vulnerabilities, performance issues, and code quality problems

/**
 * @file N+1 query detector
 * @description Detects potential N+1 query patterns with context awareness
 */

const { detectExecutionContext } = require('./contextDetector');

/**
 * Detects potential N+1 query patterns
 * @param {string} content - File content
 * @param {string} filePath - Path to the file
 * @returns {Array} Array of N+1 query issues
 */
function detectNPlusOne(content, filePath) {
  const issues = [];
  
  // Get execution context to avoid false positives
  const context = detectExecutionContext(content, filePath);
  
  // Skip CLI tools - they rarely have database operations
  if (context.type === 'cli' || context.isCLI) {
    return issues;
  }
  
  // Skip test files unless they have clear database setup
  if (context.type === 'test' && !hasTestDatabaseSetup(content)) {
    return issues;
  }
  
  const loops = [
    /for\s*\(\s*(let|const|var)\s+.+\)/,
    /\.forEach\s*\(/,
    /\.map\s*\(/,
    /while\s*\(/
  ];
  
  // More specific database patterns to reduce false positives
  const dbPatterns = [
    // Direct database calls
    /db\.query\s*\(/,
    /database\.query\s*\(/,
    /connection\.query\s*\(/,
    
    // ORM patterns with context
    /Model\.(find|findOne|findAll)\s*\(/,
    /\.find\s*\(\s*{.*}\s*\)/,  // Object-based find (not array.find())
    /\.findOne\s*\(\s*{.*}\s*\)/,
    /\.findById\s*\(/,
    /\.findWhere\s*\(/,
    
    // SQL patterns
    /SELECT\s+.*FROM.*WHERE/i,
    /INSERT\s+INTO.*VALUES/i,
    /UPDATE\s+.*SET.*WHERE/i,
    
    // Async database operations
    /await\s+.*\.(query|find|findOne|get|fetch)\s*\([^)]*{/,
    /\.then\s*\(\s*.*\.(query|find|findOne)/
  ];
  
  const hasLoop = loops.some(pattern => pattern.test(content));
  const hasDbCall = dbPatterns.some(pattern => pattern.test(content));
  
  // Additional validation: must have database-related imports or setup
  const hasDatabaseContext = hasDatabaseImportsOrSetup(content);
  
  if (hasLoop && hasDbCall && hasDatabaseContext) {
    const severity = context.type === 'server' ? 'HIGH' : 'MEDIUM';
    
    issues.push({
      type: 'n_plus_one',
      severity,
      category: 'Database',
      location: filePath,
      pattern: 'Loop + Database Query',
      summary: `Possible N+1 query pattern in ${context.type} context: database calls inside loops`,
      recommendation: context.type === 'server' 
        ? 'CRITICAL: Refactor with batched queries, joins, or eager loading to prevent server overload'
        : 'Consider batching database operations to improve performance',
      impact: context.type === 'server'
        ? 'Can cause exponential database load growth affecting all users'
        : 'May cause performance issues with large datasets',
      context: context.type
    });
  }
  
  return issues;
}

/**
 * Check if content has database-related imports or setup
 * @param {string} content - File content
 * @returns {boolean} True if database context is present
 */
function hasDatabaseImportsOrSetup(content) {
  const dbContextPatterns = [
    // Database libraries
    /require\s*\(\s*['"`]mysql['"`]\s*\)/,
    /require\s*\(\s*['"`]pg['"`]\s*\)/,
    /require\s*\(\s*['"`]mongodb['"`]\s*\)/,
    /require\s*\(\s*['"`]mongoose['"`]\s*\)/,
    /require\s*\(\s*['"`]sequelize['"`]\s*\)/,
    /import.*from\s+['"`](mysql|pg|mongodb|mongoose|sequelize)['"`]/,
    
    // Database variables
    /\b(db|database|connection|pool|client)\s*=/,
    /\b(DB_|DATABASE_)/,
    
    // Common ORM/database setup
    /mongoose\.connect/,
    /createConnection/,
    /new.*Client/,
    /\.authenticate\s*\(\)/
  ];
  
  return dbContextPatterns.some(pattern => pattern.test(content));
}

/**
 * Check if test file has database setup
 * @param {string} content - File content
 * @returns {boolean} True if test has database setup
 */
function hasTestDatabaseSetup(content) {
  return /beforeEach.*db|beforeAll.*db|setupDatabase|createTestDb/i.test(content);
}

module.exports = {
  detectNPlusOne
};