🔧 Module Augmentation: Extending Existing Modules

🎯 Introduction

Welcome to the enhancement workshop of module mastery! 🔧 If working with third-party libraries were like having a Swiss Army knife, then module augmentation is like being able to add your own custom tools to that knife without breaking it, voiding the warranty, or affecting anyone else who uses the same model - you get all the original functionality plus your own specialized enhancements!

Module augmentation allows you to extend existing modules with additional properties, methods, and types while maintaining type safety and compatibility. This powerful feature is particularly valuable when working with third-party libraries that don’t quite have everything you need, or when you want to add domain-specific functionality to external dependencies.

By the end of this tutorial, you’ll be a module augmentation expert, capable of safely and effectively extending any module to perfectly fit your application’s needs while maintaining clean, type-safe code that won’t break when dependencies update. Let’s master the art of surgical module enhancement! 🌟

📚 Understanding Module Augmentation

🤔 What Is Module Augmentation?

Module augmentation is the process of extending existing modules by adding new declarations, properties, or methods. Unlike global augmentation which affects the global scope, module augmentation targets specific modules, allowing you to enhance libraries and dependencies in a controlled, type-safe manner.

// 🌟 Basic module augmentation examples

// Extending a popular utility library
declare module 'lodash' {
  interface LoDashStatic {
    // Add custom utility methods
    customChunk<T>(array: T[], size: number, fillValue?: T): T[][];
    safeGet<T>(object: any, path: string, defaultValue?: T): T;
    deepMergeCustom<T>(target: T, ...sources: Partial<T>[]): T;
  }
}

// Extending Express.js Request interface
declare module 'express-serve-static-core' {
  interface Request {
    // Add custom properties for authentication
    user?: {
      id: string;
      email: string;
      roles: string[];
      permissions: string[];
    };
    
    // Add request tracking
    requestId: string;
    startTime: number;
    
    // Add custom validation results
    validationErrors?: ValidationError[];
    sanitizedBody?: any;
  }
  
  interface Response {
    // Add custom response methods
    apiSuccess<T>(data: T, message?: string): Response;
    apiError(error: string, statusCode?: number): Response;
    sendPaginated<T>(data: T[], pagination: PaginationInfo): Response;
  }
}

interface ValidationError {
  field: string;
  message: string;
  value: any;
}

interface PaginationInfo {
  page: number;
  limit: number;
  total: number;
  hasNext: boolean;
  hasPrev: boolean;
}

// 🎯 Extending React component props
declare module 'react' {
  interface HTMLAttributes<T> {
    // Add custom data attributes with type safety
    'data-testid'?: string;
    'data-analytics-id'?: string;
    'data-feature-flag'?: string;
  }
  
  interface CSSProperties {
    // Add CSS custom properties
    '--primary-color'?: string;
    '--secondary-color'?: string;
    '--border-radius'?: string;
    '--spacing-unit'?: string;
  }
}

// 🔧 Extending Node.js process object
declare module 'process' {
  global {
    namespace NodeJS {
      interface Process {
        // Add custom process properties
        appConfig: AppConfig;
        buildInfo: BuildInfo;
        featureFlags: FeatureFlags;
      }
    }
  }
}

interface AppConfig {
  environment: 'development' | 'staging' | 'production';
  apiUrl: string;
  databaseUrl: string;
  redisUrl: string;
  secretKey: string;
}

interface BuildInfo {
  version: string;
  buildDate: string;
  gitCommit: string;
  buildNumber: number;
}

interface FeatureFlags {
  enableNewFeature: boolean;
  useExperimentalAlgorithm: boolean;
  enableAdvancedLogging: boolean;
}

// ✨ Usage examples with type safety
import _ from 'lodash';
import express from 'express';

// Lodash with custom methods
const chunks = _.customChunk([1, 2, 3, 4, 5], 2, 0); // Type: number[][]
const value = _.safeGet(someObject, 'nested.property', 'default'); // Type: string

// Express with enhanced Request/Response
const app = express();

app.use((req, res, next) => {
  req.requestId = generateRequestId();
  req.startTime = Date.now();
  next();
});

app.post('/api/users', (req, res) => {
  // req.user is now properly typed
  if (!req.user) {
    return res.apiError('Authentication required', 401);
  }
  
  // Validation results are typed
  if (req.validationErrors?.length) {
    return res.apiError('Validation failed', 400);
  }
  
  // Custom success response
  res.apiSuccess(userData, 'User created successfully');
});

🏗️ Advanced Module Augmentation Patterns

// 🚀 Conditional module augmentation based on configuration

// Create a configuration-driven augmentation system
interface AugmentationConfig {
  enableLogging: boolean;
  enableMetrics: boolean;
  enableSecurity: boolean;
  customUtilities: boolean;
}

// Conditional augmentation for Array prototype
declare module 'array-augmentation' {
  interface AugmentationConfig {
    enableLogging: boolean;
    enableMetrics: boolean;
  }
}

declare global {
  interface Array<T> {
    // Conditionally add logging methods
    withLogging(this: T[], operation: string): T[];
    
    // Conditionally add metrics methods
    withMetrics(this: T[], metricName: string): T[];
    
    // Custom find methods
    findByProperty<K extends keyof T>(property: K, value: T[K]): T | undefined;
    findAllByProperty<K extends keyof T>(property: K, value: T[K]): T[];
    
    // Statistical methods
    average(this: number[]): number;
    median(this: number[]): number;
    mode(this: number[]): number[];
    
    // Functional programming utilities
    pipe<U>(this: T[], ...fns: Array<(arr: T[]) => U>): U;
    groupBy<K extends keyof T>(property: K): Record<string, T[]>;
    partition(predicate: (item: T) => boolean): [T[], T[]];
  }
}

// 🎨 Advanced third-party library augmentation
declare module 'moment' {
  interface Moment {
    // Business-specific date methods
    toBusinessDays(): number;
    addBusinessDays(days: number): Moment;
    isBusinessDay(): boolean;
    getQuarter(): number;
    
    // Formatting utilities
    toApiFormat(): string;
    toDisplayFormat(): string;
    toFileNameFormat(): string;
    
    // Validation methods
    isValidBusinessDate(): boolean;
    isWithinBusinessHours(): boolean;
    isHoliday(holidays: Date[]): boolean;
  }
  
  interface MomentStatic {
    // Static utility methods
    createBusinessDay(year: number, month: number, day: number): Moment;
    getBusinessDaysInMonth(year: number, month: number): number;
    getNextBusinessDay(from?: Moment): Moment;
    getPreviousBusinessDay(from?: Moment): Moment;
  }
}

// 🔒 Security-focused module augmentation
declare module 'crypto' {
  interface Hash {
    // Enhanced hash methods with security best practices
    hashWithSalt(data: string, salt: string, iterations?: number): string;
    verifyHash(data: string, hash: string, salt: string): boolean;
    
    // Timing-safe comparison
    timingSafeEquals(a: string, b: string): boolean;
  }
  
  interface Hmac {
    // JWT-specific HMAC methods
    signJWT(payload: object, secret: string, expiresIn?: string): string;
    verifyJWT(token: string, secret: string): object | null;
    
    // API signature methods
    generateAPISignature(method: string, url: string, body: string, timestamp: number): string;
    verifyAPISignature(signature: string, method: string, url: string, body: string, timestamp: number): boolean;
  }
}

// 🌐 HTTP client augmentation
declare module 'axios' {
  interface AxiosRequestConfig {
    // Custom configuration options
    retryConfig?: RetryConfig;
    circuitBreaker?: CircuitBreakerConfig;
    cacheConfig?: CacheConfig;
    telemetryConfig?: TelemetryConfig;
  }
  
  interface AxiosResponse<T = any> {
    // Enhanced response metadata
    timing: ResponseTiming;
    cacheStatus: CacheStatus;
    retryInfo: RetryInfo;
  }
  
  interface AxiosInstance {
    // Custom methods for common patterns
    getWithCache<T>(url: string, config?: AxiosRequestConfig): Promise<AxiosResponse<T>>;
    postWithRetry<T>(url: string, data?: any, config?: AxiosRequestConfig): Promise<AxiosResponse<T>>;
    uploadWithProgress<T>(url: string, file: File, onProgress?: (progress: number) => void): Promise<AxiosResponse<T>>;
    
    // Batch operations
    batchGet<T>(urls: string[], config?: AxiosRequestConfig): Promise<AxiosResponse<T>[]>;
    batchPost<T>(requests: BatchRequest[], config?: AxiosRequestConfig): Promise<AxiosResponse<T>[]>;
  }
}

interface RetryConfig {
  maxRetries: number;
  baseDelay: number;
  maxDelay: number;
  backoffFactor: number;
  retryCondition?: (error: any) => boolean;
}

interface CircuitBreakerConfig {
  threshold: number;
  timeout: number;
  resetTimeout: number;
}

interface CacheConfig {
  ttl: number;
  key?: string;
  tags?: string[];
}

interface TelemetryConfig {
  traceId?: string;
  spanId?: string;
  operationName?: string;
}

interface ResponseTiming {
  dns: number;
  tcp: number;
  tls: number;
  firstByte: number;
  download: number;
  total: number;
}

interface CacheStatus {
  hit: boolean;
  ttl: number;
  age: number;
}

interface RetryInfo {
  attemptCount: number;
  totalDelay: number;
  lastError?: Error;
}

interface BatchRequest {
  url: string;
  method: 'GET' | 'POST' | 'PUT' | 'DELETE';
  data?: any;
  config?: AxiosRequestConfig;
}

🛠️ Building a Module Augmentation Management System

Let’s create a comprehensive system for managing module augmentations in large applications:

// 🏗️ Module Augmentation Registry and Management System

namespace ModuleAugmentation {
  
  // 📋 Registry for tracking augmentations
  export interface AugmentationRegistry {
    modules: Map<string, ModuleAugmentationInfo>;
    dependencies: Map<string, string[]>;
    conflicts: AugmentationConflict[];
    metadata: RegistryMetadata;
  }
  
  export interface ModuleAugmentationInfo {
    moduleName: string;
    augmentations: AugmentationDefinition[];
    version: string;
    dependencies: string[];
    conflicts: string[];
    author: string;
    description: string;
    createdAt: Date;
    lastModified: Date;
  }
  
  export interface AugmentationDefinition {
    name: string;
    type: AugmentationType;
    target: string;
    properties: PropertyDefinition[];
    methods: MethodDefinition[];
    interfaces: InterfaceDefinition[];
    safety: SafetyAnalysis;
  }
  
  export type AugmentationType = 'interface' | 'namespace' | 'global' | 'prototype' | 'static';
  
  export interface PropertyDefinition {
    name: string;
    type: string;
    optional: boolean;
    readonly: boolean;
    description: string;
    examples: string[];
  }
  
  export interface MethodDefinition {
    name: string;
    signature: string;
    returnType: string;
    parameters: ParameterDefinition[];
    description: string;
    examples: string[];
    complexity: 'low' | 'medium' | 'high';
  }
  
  export interface ParameterDefinition {
    name: string;
    type: string;
    optional: boolean;
    defaultValue?: any;
    description: string;
  }
  
  export interface InterfaceDefinition {
    name: string;
    extends: string[];
    properties: PropertyDefinition[];
    methods: MethodDefinition[];
    generics: GenericDefinition[];
  }
  
  export interface GenericDefinition {
    name: string;
    constraint?: string;
    defaultType?: string;
  }
  
  export interface SafetyAnalysis {
    conflictRisk: 'low' | 'medium' | 'high';
    breakingChangeRisk: 'low' | 'medium' | 'high';
    performanceImpact: 'negligible' | 'minor' | 'moderate' | 'significant';
    testCoverage: number;
    documentationScore: number;
  }
  
  export interface AugmentationConflict {
    augmentation1: string;
    augmentation2: string;
    conflictType: ConflictType;
    severity: 'warning' | 'error' | 'critical';
    description: string;
    resolution?: string;
  }
  
  export type ConflictType = 'naming' | 'signature' | 'behavior' | 'dependency' | 'version';
  
  export interface RegistryMetadata {
    version: string;
    lastUpdated: Date;
    totalAugmentations: number;
    totalModules: number;
    healthScore: number;
  }
  
  // 🔧 Augmentation Manager
  export class AugmentationManager {
    private registry: AugmentationRegistry;
    private validators: AugmentationValidator[];
    private logger: AugmentationLogger;
    
    constructor() {
      this.registry = this.initializeRegistry();
      this.validators = this.createValidators();
      this.logger = new AugmentationLogger();
    }
    
    // 📝 Register a new module augmentation
    registerAugmentation(info: ModuleAugmentationInfo): RegisterResult {
      console.log(`📝 Registering augmentation for module: ${info.moduleName}`);
      
      try {
        // Validate the augmentation
        const validationResult = this.validateAugmentation(info);
        if (!validationResult.isValid) {
          return {
            success: false,
            errors: validationResult.errors,
            warnings: validationResult.warnings
          };
        }
        
        // Check for conflicts
        const conflicts = this.detectConflicts(info);
        if (conflicts.some(c => c.severity === 'critical')) {
          return {
            success: false,
            errors: conflicts.filter(c => c.severity === 'critical').map(c => c.description),
            warnings: conflicts.filter(c => c.severity !== 'critical').map(c => c.description)
          };
        }
        
        // Register the augmentation
        this.registry.modules.set(info.moduleName, info);
        this.updateDependencies(info);
        this.updateMetadata();
        
        this.logger.logRegistration(info);
        
        return {
          success: true,
          info: `Successfully registered augmentation for ${info.moduleName}`,
          warnings: conflicts.filter(c => c.severity === 'warning').map(c => c.description)
        };
        
      } catch (error) {
        this.logger.logError('Registration failed', error);
        return {
          success: false,
          errors: [`Registration failed: ${error.message}`]
        };
      }
    }
    
    // 🔍 Analyze augmentation safety
    analyzeAugmentation(moduleName: string): SafetyReport {
      console.log(`🔍 Analyzing safety for module: ${moduleName}`);
      
      const moduleInfo = this.registry.modules.get(moduleName);
      if (!moduleInfo) {
        throw new Error(`Module ${moduleName} not found in registry`);
      }
      
      const conflicts = this.detectConflicts(moduleInfo);
      const dependencies = this.analyzeDependencies(moduleName);
      const riskAssessment = this.assessRisks(moduleInfo);
      
      return {
        moduleName,
        overallSafety: this.calculateOverallSafety(conflicts, dependencies, riskAssessment),
        conflicts,
        dependencies,
        riskAssessment,
        recommendations: this.generateRecommendations(moduleInfo, conflicts, riskAssessment),
        generatedAt: new Date()
      };
    }
    
    // 🔄 Update an existing augmentation
    updateAugmentation(moduleName: string, updates: Partial<ModuleAugmentationInfo>): UpdateResult {
      console.log(`🔄 Updating augmentation for module: ${moduleName}`);
      
      const existingInfo = this.registry.modules.get(moduleName);
      if (!existingInfo) {
        return {
          success: false,
          error: `Module ${moduleName} not found in registry`
        };
      }
      
      const updatedInfo = { ...existingInfo, ...updates, lastModified: new Date() };
      
      // Validate the updated augmentation
      const validationResult = this.validateAugmentation(updatedInfo);
      if (!validationResult.isValid) {
        return {
          success: false,
          error: 'Updated augmentation failed validation',
          details: validationResult.errors
        };
      }
      
      // Check for new conflicts
      const conflicts = this.detectConflicts(updatedInfo);
      const criticalConflicts = conflicts.filter(c => c.severity === 'critical');
      
      if (criticalConflicts.length > 0) {
        return {
          success: false,
          error: 'Update would introduce critical conflicts',
          details: criticalConflicts.map(c => c.description)
        };
      }
      
      // Apply the update
      this.registry.modules.set(moduleName, updatedInfo);
      this.updateDependencies(updatedInfo);
      this.updateMetadata();
      
      this.logger.logUpdate(moduleName, updates);
      
      return {
        success: true,
        message: `Successfully updated augmentation for ${moduleName}`,
        warnings: conflicts.filter(c => c.severity === 'warning').map(c => c.description)
      };
    }
    
    // 🗑️ Remove an augmentation
    removeAugmentation(moduleName: string): RemovalResult {
      console.log(`🗑️ Removing augmentation for module: ${moduleName}`);
      
      if (!this.registry.modules.has(moduleName)) {
        return {
          success: false,
          error: `Module ${moduleName} not found in registry`
        };
      }
      
      // Check for dependencies
      const dependents = this.findDependents(moduleName);
      if (dependents.length > 0) {
        return {
          success: false,
          error: `Cannot remove ${moduleName}: other modules depend on it`,
          details: dependents
        };
      }
      
      // Remove the augmentation
      this.registry.modules.delete(moduleName);
      this.cleanupDependencies(moduleName);
      this.updateMetadata();
      
      this.logger.logRemoval(moduleName);
      
      return {
        success: true,
        message: `Successfully removed augmentation for ${moduleName}`
      };
    }
    
    // 📊 Generate comprehensive report
    generateReport(): AugmentationReport {
      console.log('📊 Generating comprehensive augmentation report');
      
      const modules = Array.from(this.registry.modules.values());
      const totalAugmentations = modules.reduce((sum, module) => sum + module.augmentations.length, 0);
      
      return {
        summary: {
          totalModules: modules.length,
          totalAugmentations,
          averageComplexity: this.calculateAverageComplexity(modules),
          healthScore: this.registry.metadata.healthScore,
          lastUpdated: this.registry.metadata.lastUpdated
        },
        moduleBreakdown: modules.map(module => ({
          name: module.moduleName,
          augmentationCount: module.augmentations.length,
          riskLevel: this.calculateModuleRisk(module),
          lastModified: module.lastModified
        })),
        conflicts: this.registry.conflicts,
        recommendations: this.generateGlobalRecommendations(),
        metrics: this.calculateMetrics(),
        generatedAt: new Date()
      };
    }
    
    // 🔍 Private helper methods
    private initializeRegistry(): AugmentationRegistry {
      return {
        modules: new Map(),
        dependencies: new Map(),
        conflicts: [],
        metadata: {
          version: '1.0.0',
          lastUpdated: new Date(),
          totalAugmentations: 0,
          totalModules: 0,
          healthScore: 100
        }
      };
    }
    
    private createValidators(): AugmentationValidator[] {
      return [
        new SyntaxValidator(),
        new ConflictValidator(),
        new SecurityValidator(),
        new PerformanceValidator(),
        new CompatibilityValidator()
      ];
    }
    
    private validateAugmentation(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      for (const validator of this.validators) {
        const result = validator.validate(info);
        errors.push(...result.errors);
        warnings.push(...result.warnings);
      }
      
      return {
        isValid: errors.length === 0,
        errors,
        warnings
      };
    }
    
    private detectConflicts(info: ModuleAugmentationInfo): AugmentationConflict[] {
      const conflicts: AugmentationConflict[] = [];
      
      // Check against existing modules
      for (const [existingName, existingInfo] of this.registry.modules) {
        if (existingName === info.moduleName) continue;
        
        const moduleConflicts = this.findModuleConflicts(info, existingInfo);
        conflicts.push(...moduleConflicts);
      }
      
      return conflicts;
    }
    
    private findModuleConflicts(
      module1: ModuleAugmentationInfo, 
      module2: ModuleAugmentationInfo
    ): AugmentationConflict[] {
      const conflicts: AugmentationConflict[] = [];
      
      // Check for naming conflicts
      for (const aug1 of module1.augmentations) {
        for (const aug2 of module2.augmentations) {
          if (aug1.target === aug2.target) {
            // Check for method/property name conflicts
            const nameConflicts = this.findNamingConflicts(aug1, aug2);
            conflicts.push(...nameConflicts.map(conflict => ({
              augmentation1: `${module1.moduleName}.${aug1.name}`,
              augmentation2: `${module2.moduleName}.${aug2.name}`,
              conflictType: 'naming' as ConflictType,
              severity: 'warning' as const,
              description: `Naming conflict: ${conflict}`,
              resolution: `Consider renaming one of the conflicting members`
            })));
          }
        }
      }
      
      return conflicts;
    }
    
    private findNamingConflicts(aug1: AugmentationDefinition, aug2: AugmentationDefinition): string[] {
      const conflicts: string[] = [];
      
      // Check property conflicts
      for (const prop1 of aug1.properties) {
        for (const prop2 of aug2.properties) {
          if (prop1.name === prop2.name && prop1.type !== prop2.type) {
            conflicts.push(`Property ${prop1.name} has different types`);
          }
        }
      }
      
      // Check method conflicts
      for (const method1 of aug1.methods) {
        for (const method2 of aug2.methods) {
          if (method1.name === method2.name && method1.signature !== method2.signature) {
            conflicts.push(`Method ${method1.name} has different signatures`);
          }
        }
      }
      
      return conflicts;
    }
    
    private updateDependencies(info: ModuleAugmentationInfo): void {
      this.registry.dependencies.set(info.moduleName, info.dependencies);
      
      // Update reverse dependencies
      for (const dependency of info.dependencies) {
        const dependents = this.registry.dependencies.get(dependency) || [];
        if (!dependents.includes(info.moduleName)) {
          dependents.push(info.moduleName);
          this.registry.dependencies.set(dependency, dependents);
        }
      }
    }
    
    private updateMetadata(): void {
      this.registry.metadata.lastUpdated = new Date();
      this.registry.metadata.totalModules = this.registry.modules.size;
      this.registry.metadata.totalAugmentations = Array.from(this.registry.modules.values())
        .reduce((sum, module) => sum + module.augmentations.length, 0);
      this.registry.metadata.healthScore = this.calculateHealthScore();
    }
    
    private calculateHealthScore(): number {
      const totalModules = this.registry.modules.size;
      if (totalModules === 0) return 100;
      
      const criticalConflicts = this.registry.conflicts.filter(c => c.severity === 'critical').length;
      const warningConflicts = this.registry.conflicts.filter(c => c.severity === 'warning').length;
      
      const conflictPenalty = (criticalConflicts * 20) + (warningConflicts * 5);
      const baseScore = 100 - Math.min(conflictPenalty, 80);
      
      return Math.max(baseScore, 20);
    }
    
    private analyzeDependencies(moduleName: string): DependencyAnalysis {
      const dependencies = this.registry.dependencies.get(moduleName) || [];
      const dependents = this.findDependents(moduleName);
      
      return {
        directDependencies: dependencies,
        dependents,
        circularDependencies: this.findCircularDependencies(moduleName),
        depth: this.calculateDependencyDepth(moduleName),
        criticalPath: this.findCriticalPath(moduleName)
      };
    }
    
    private findDependents(moduleName: string): string[] {
      const dependents: string[] = [];
      
      for (const [module, deps] of this.registry.dependencies) {
        if (deps.includes(moduleName)) {
          dependents.push(module);
        }
      }
      
      return dependents;
    }
    
    private findCircularDependencies(moduleName: string): string[][] {
      // Implementation for detecting circular dependencies
      return [];
    }
    
    private calculateDependencyDepth(moduleName: string): number {
      // Implementation for calculating dependency depth
      return 0;
    }
    
    private findCriticalPath(moduleName: string): string[] {
      // Implementation for finding critical dependency path
      return [];
    }
    
    private assessRisks(info: ModuleAugmentationInfo): RiskAssessment {
      return {
        breakingChangeRisk: this.assessBreakingChangeRisk(info),
        performanceRisk: this.assessPerformanceRisk(info),
        securityRisk: this.assessSecurityRisk(info),
        maintenanceRisk: this.assessMaintenanceRisk(info),
        overallRisk: 'low'
      };
    }
    
    private assessBreakingChangeRisk(info: ModuleAugmentationInfo): 'low' | 'medium' | 'high' {
      // Implementation for assessing breaking change risk
      return 'low';
    }
    
    private assessPerformanceRisk(info: ModuleAugmentationInfo): 'low' | 'medium' | 'high' {
      // Implementation for assessing performance risk
      return 'low';
    }
    
    private assessSecurityRisk(info: ModuleAugmentationInfo): 'low' | 'medium' | 'high' {
      // Implementation for assessing security risk
      return 'low';
    }
    
    private assessMaintenanceRisk(info: ModuleAugmentationInfo): 'low' | 'medium' | 'high' {
      // Implementation for assessing maintenance risk
      return 'low';
    }
    
    private calculateOverallSafety(
      conflicts: AugmentationConflict[],
      dependencies: DependencyAnalysis,
      risks: RiskAssessment
    ): SafetyLevel {
      // Implementation for calculating overall safety level
      return 'safe';
    }
    
    private generateRecommendations(
      info: ModuleAugmentationInfo,
      conflicts: AugmentationConflict[],
      risks: RiskAssessment
    ): string[] {
      const recommendations: string[] = [];
      
      if (conflicts.length > 0) {
        recommendations.push('Review and resolve naming conflicts');
      }
      
      if (risks.overallRisk === 'high') {
        recommendations.push('Consider refactoring to reduce risk');
      }
      
      return recommendations;
    }
    
    private generateGlobalRecommendations(): string[] {
      return [
        'Regular dependency audits',
        'Automated conflict detection',
        'Documentation updates'
      ];
    }
    
    private calculateAverageComplexity(modules: ModuleAugmentationInfo[]): number {
      if (modules.length === 0) return 0;
      
      const totalComplexity = modules.reduce((sum, module) => {
        return sum + module.augmentations.reduce((augSum, aug) => {
          return augSum + aug.methods.reduce((methodSum, method) => {
            const complexityScore = method.complexity === 'low' ? 1 : 
                                   method.complexity === 'medium' ? 2 : 3;
            return methodSum + complexityScore;
          }, 0);
        }, 0);
      }, 0);
      
      const totalMethods = modules.reduce((sum, module) => {
        return sum + module.augmentations.reduce((augSum, aug) => {
          return augSum + aug.methods.length;
        }, 0);
      }, 0);
      
      return totalMethods > 0 ? totalComplexity / totalMethods : 0;
    }
    
    private calculateModuleRisk(module: ModuleAugmentationInfo): 'low' | 'medium' | 'high' {
      // Implementation for calculating individual module risk
      return 'low';
    }
    
    private calculateMetrics(): AugmentationMetrics {
      return {
        totalLines: 0,
        averageMethodsPerAugmentation: 0,
        testCoverageAverage: 0,
        documentationScore: 0
      };
    }
    
    private cleanupDependencies(moduleName: string): void {
      this.registry.dependencies.delete(moduleName);
      
      // Remove from other modules' dependency lists
      for (const [module, deps] of this.registry.dependencies) {
        const index = deps.indexOf(moduleName);
        if (index !== -1) {
          deps.splice(index, 1);
        }
      }
    }
  }
  
  // 🔍 Validator interfaces and implementations
  abstract class AugmentationValidator {
    abstract validate(info: ModuleAugmentationInfo): ValidationResult;
  }
  
  class SyntaxValidator extends AugmentationValidator {
    validate(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      // Validate syntax of augmentation definitions
      for (const augmentation of info.augmentations) {
        if (!augmentation.name || augmentation.name.trim() === '') {
          errors.push('Augmentation name cannot be empty');
        }
        
        if (!augmentation.target || augmentation.target.trim() === '') {
          errors.push('Augmentation target cannot be empty');
        }
        
        // Validate method signatures
        for (const method of augmentation.methods) {
          if (!this.isValidTypeScriptSignature(method.signature)) {
            errors.push(`Invalid method signature: ${method.signature}`);
          }
        }
      }
      
      return { isValid: errors.length === 0, errors, warnings };
    }
    
    private isValidTypeScriptSignature(signature: string): boolean {
      // Basic signature validation
      return signature.includes('(') && signature.includes(')');
    }
  }
  
  class ConflictValidator extends AugmentationValidator {
    validate(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      // Check for internal conflicts within the module
      const names = new Set<string>();
      
      for (const augmentation of info.augmentations) {
        for (const method of augmentation.methods) {
          if (names.has(method.name)) {
            warnings.push(`Duplicate method name: ${method.name}`);
          }
          names.add(method.name);
        }
        
        for (const property of augmentation.properties) {
          if (names.has(property.name)) {
            warnings.push(`Duplicate property name: ${property.name}`);
          }
          names.add(property.name);
        }
      }
      
      return { isValid: errors.length === 0, errors, warnings };
    }
  }
  
  class SecurityValidator extends AugmentationValidator {
    validate(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      // Check for potential security risks
      for (const augmentation of info.augmentations) {
        // Check for prototype pollution risks
        if (augmentation.type === 'prototype') {
          warnings.push('Prototype augmentation may pose security risks');
        }
        
        // Check for eval-like method names
        for (const method of augmentation.methods) {
          if (method.name.includes('eval') || method.name.includes('exec')) {
            warnings.push(`Method name '${method.name}' may indicate unsafe operations`);
          }
        }
      }
      
      return { isValid: errors.length === 0, errors, warnings };
    }
  }
  
  class PerformanceValidator extends AugmentationValidator {
    validate(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      // Check for potential performance issues
      for (const augmentation of info.augmentations) {
        if (augmentation.methods.length > 20) {
          warnings.push(`Large number of methods (${augmentation.methods.length}) may impact performance`);
        }
        
        for (const method of augmentation.methods) {
          if (method.complexity === 'high') {
            warnings.push(`High complexity method '${method.name}' may impact performance`);
          }
        }
      }
      
      return { isValid: errors.length === 0, errors, warnings };
    }
  }
  
  class CompatibilityValidator extends AugmentationValidator {
    validate(info: ModuleAugmentationInfo): ValidationResult {
      const errors: string[] = [];
      const warnings: string[] = [];
      
      // Check for compatibility issues
      if (!info.version || !this.isValidVersion(info.version)) {
        errors.push('Invalid or missing version number');
      }
      
      // Check dependency versions
      for (const dependency of info.dependencies) {
        if (!this.isDependencyAvailable(dependency)) {
          warnings.push(`Dependency '${dependency}' may not be available`);
        }
      }
      
      return { isValid: errors.length === 0, errors, warnings };
    }
    
    private isValidVersion(version: string): boolean {
      return /^\d+\.\d+\.\d+$/.test(version);
    }
    
    private isDependencyAvailable(dependency: string): boolean {
      // Check if dependency is available
      return true;
    }
  }
  
  // 📝 Logger for augmentation operations
  class AugmentationLogger {
    private logs: AugmentationLog[] = [];
    
    logRegistration(info: ModuleAugmentationInfo): void {
      this.addLog({
        type: 'registration',
        module: info.moduleName,
        message: `Registered augmentation for ${info.moduleName}`,
        timestamp: new Date(),
        metadata: { augmentationCount: info.augmentations.length }
      });
    }
    
    logUpdate(moduleName: string, updates: Partial<ModuleAugmentationInfo>): void {
      this.addLog({
        type: 'update',
        module: moduleName,
        message: `Updated augmentation for ${moduleName}`,
        timestamp: new Date(),
        metadata: { updates: Object.keys(updates) }
      });
    }
    
    logRemoval(moduleName: string): void {
      this.addLog({
        type: 'removal',
        module: moduleName,
        message: `Removed augmentation for ${moduleName}`,
        timestamp: new Date(),
        metadata: {}
      });
    }
    
    logError(message: string, error: any): void {
      this.addLog({
        type: 'error',
        module: 'system',
        message,
        timestamp: new Date(),
        metadata: { error: error.message, stack: error.stack }
      });
    }
    
    private addLog(log: AugmentationLog): void {
      this.logs.push(log);
      console.log(`[${log.timestamp.toISOString()}] ${log.type.toUpperCase()}: ${log.message}`);
      
      // Keep only the last 1000 logs
      if (this.logs.length > 1000) {
        this.logs = this.logs.slice(-1000);
      }
    }
    
    getLogs(filter?: LogFilter): AugmentationLog[] {
      if (!filter) return [...this.logs];
      
      return this.logs.filter(log => {
        if (filter.type && log.type !== filter.type) return false;
        if (filter.module && log.module !== filter.module) return false;
        if (filter.since && log.timestamp < filter.since) return false;
        if (filter.until && log.timestamp > filter.until) return false;
        return true;
      });
    }
  }
  
  // 📊 Supporting interfaces
  interface ValidationResult {
    isValid: boolean;
    errors: string[];
    warnings: string[];
  }
  
  interface RegisterResult {
    success: boolean;
    errors?: string[];
    warnings?: string[];
    info?: string;
  }
  
  interface UpdateResult {
    success: boolean;
    error?: string;
    details?: string[];
    message?: string;
    warnings?: string[];
  }
  
  interface RemovalResult {
    success: boolean;
    error?: string;
    details?: string[];
    message?: string;
  }
  
  interface SafetyReport {
    moduleName: string;
    overallSafety: SafetyLevel;
    conflicts: AugmentationConflict[];
    dependencies: DependencyAnalysis;
    riskAssessment: RiskAssessment;
    recommendations: string[];
    generatedAt: Date;
  }
  
  type SafetyLevel = 'safe' | 'caution' | 'unsafe';
  
  interface DependencyAnalysis {
    directDependencies: string[];
    dependents: string[];
    circularDependencies: string[][];
    depth: number;
    criticalPath: string[];
  }
  
  interface RiskAssessment {
    breakingChangeRisk: 'low' | 'medium' | 'high';
    performanceRisk: 'low' | 'medium' | 'high';
    securityRisk: 'low' | 'medium' | 'high';
    maintenanceRisk: 'low' | 'medium' | 'high';
    overallRisk: 'low' | 'medium' | 'high';
  }
  
  interface AugmentationReport {
    summary: ReportSummary;
    moduleBreakdown: ModuleBreakdown[];
    conflicts: AugmentationConflict[];
    recommendations: string[];
    metrics: AugmentationMetrics;
    generatedAt: Date;
  }
  
  interface ReportSummary {
    totalModules: number;
    totalAugmentations: number;
    averageComplexity: number;
    healthScore: number;
    lastUpdated: Date;
  }
  
  interface ModuleBreakdown {
    name: string;
    augmentationCount: number;
    riskLevel: 'low' | 'medium' | 'high';
    lastModified: Date;
  }
  
  interface AugmentationMetrics {
    totalLines: number;
    averageMethodsPerAugmentation: number;
    testCoverageAverage: number;
    documentationScore: number;
  }
  
  interface AugmentationLog {
    type: 'registration' | 'update' | 'removal' | 'error' | 'warning';
    module: string;
    message: string;
    timestamp: Date;
    metadata: any;
  }
  
  interface LogFilter {
    type?: 'registration' | 'update' | 'removal' | 'error' | 'warning';
    module?: string;
    since?: Date;
    until?: Date;
  }
}

// 🚀 Usage examples with the management system
const augmentationManager = new ModuleAugmentation.AugmentationManager();

// Register a new Express.js augmentation
const expressAugmentation: ModuleAugmentation.ModuleAugmentationInfo = {
  moduleName: 'express',
  augmentations: [{
    name: 'CustomRequestMethods',
    type: 'interface',
    target: 'express.Request',
    properties: [
      {
        name: 'user',
        type: 'User | undefined',
        optional: true,
        readonly: false,
        description: 'Current authenticated user',
        examples: ['req.user?.id', 'req.user?.roles']
      }
    ],
    methods: [
      {
        name: 'getClientIP',
        signature: '(): string',
        returnType: 'string',
        parameters: [],
        description: 'Get client IP address from various headers',
        examples: ['const ip = req.getClientIP();'],
        complexity: 'low'
      }
    ],
    interfaces: [],
    safety: {
      conflictRisk: 'low',
      breakingChangeRisk: 'low',
      performanceImpact: 'negligible',
      testCoverage: 95,
      documentationScore: 90
    }
  }],
  version: '1.0.0',
  dependencies: ['express'],
  conflicts: [],
  author: 'Development Team',
  description: 'Enhanced Express.js request and response objects',
  createdAt: new Date(),
  lastModified: new Date()
};

const registerResult = augmentationManager.registerAugmentation(expressAugmentation);
console.log('Registration result:', registerResult);

// Analyze the augmentation
const safetyReport = augmentationManager.analyzeAugmentation('express');
console.log('Safety report:', safetyReport);

// Generate comprehensive report
const fullReport = augmentationManager.generateReport();
console.log('Full report:', fullReport);

🔒 Advanced Security and Type Safety Patterns

// 🛡️ Security-focused module augmentation patterns

// Type-safe environment variable augmentation
declare module 'process' {
  global {
    namespace NodeJS {
      interface ProcessEnv {
        // Required environment variables with strict typing
        NODE_ENV: 'development' | 'staging' | 'production';
        DATABASE_URL: string;
        JWT_SECRET: string;
        
        // Optional environment variables with defaults
        PORT?: string;
        LOG_LEVEL?: 'debug' | 'info' | 'warn' | 'error';
        CACHE_TTL?: string;
        
        // Feature flags with type safety
        FEATURE_NEW_AUTH?: 'true' | 'false';
        FEATURE_ADVANCED_LOGGING?: 'true' | 'false';
        
        // Security-related variables
        CORS_ORIGIN?: string;
        RATE_LIMIT_MAX?: string;
        SESSION_SECRET?: string;
      }
    }
  }
}

// Secure API client augmentation
declare module 'axios' {
  interface AxiosRequestConfig {
    // Security headers
    securityHeaders?: {
      apiKey?: string;
      signature?: string;
      timestamp?: number;
      nonce?: string;
    };
    
    // Rate limiting configuration
    rateLimitConfig?: {
      maxRequests: number;
      windowMs: number;
      skipSuccessfulRequests?: boolean;
    };
    
    // Request validation
    validation?: {
      requireHttps: boolean;
      validateOrigin: boolean;
      sanitizeInput: boolean;
    };
  }
  
  interface AxiosResponse<T = any> {
    // Security metadata
    securityInfo: {
      isSecure: boolean;
      encryptionUsed: boolean;
      signatureValid: boolean;
      rateLimit: {
        remaining: number;
        resetTime: number;
      };
    };
  }
}

// Database security augmentation
declare module 'mongoose' {
  interface DocumentQuery<T, DocType extends Document> {
    // Secure query methods that prevent injection
    secureFindOne(filter: FilterQuery<DocType>): DocumentQuery<DocType | null, DocType>;
    secureFind(filter: FilterQuery<DocType>): DocumentQuery<DocType[], DocType>;
    
    // Audit trail methods
    withAuditTrail(userId: string, action: string): this;
    
    // Data sanitization
    sanitizeInput(): this;
    
    // Performance monitoring
    withPerformanceMonitoring(): this;
  }
  
  interface Schema<T = any> {
    // Add security plugins
    addSecurityPlugin(options: SecurityPluginOptions): void;
    
    // Add field encryption
    addFieldEncryption(fields: string[], key: string): void;
    
    // Add audit logging
    addAuditLogging(options: AuditOptions): void;
  }
}

interface SecurityPluginOptions {
  preventInjection: boolean;
  auditChanges: boolean;
  encryptSensitiveFields: boolean;
  validateInput: boolean;
}

interface AuditOptions {
  trackCreation: boolean;
  trackUpdates: boolean;
  trackDeletion: boolean;
  includeUserInfo: boolean;
}

// JWT security augmentation
declare module 'jsonwebtoken' {
  interface JwtPayload {
    // Required claims for our application
    userId: string;
    email: string;
    roles: string[];
    
    // Security claims
    sessionId: string;
    ipAddress: string;
    userAgent: string;
    
    // Optional claims
    permissions?: string[];
    organizationId?: string;
    lastLoginAt?: number;
  }
  
  interface SignOptions {
    // Enhanced security options
    algorithm: 'HS256' | 'HS384' | 'HS512' | 'RS256' | 'RS384' | 'RS512';
    keyid?: string;
    
    // Custom security options
    includeFingerprint?: boolean;
    bindToIP?: boolean;
    bindToUserAgent?: boolean;
  }
  
  interface VerifyOptions {
    // Enhanced verification options
    requireClaims?: string[];
    validateFingerprint?: boolean;
    validateIPBinding?: boolean;
    validateUserAgentBinding?: boolean;
    
    // Custom validation functions
    customValidation?: (payload: JwtPayload) => boolean;
  }
}

// Crypto module security augmentation
declare module 'crypto' {
  interface Hash {
    // Secure password hashing with industry standards
    hashPasswordSecure(password: string, saltRounds?: number): Promise<string>;
    verifyPasswordSecure(password: string, hash: string): Promise<boolean>;
    
    // API signature generation
    generateHMACSignature(
      method: string, 
      url: string, 
      body: string, 
      timestamp: number, 
      secret: string
    ): string;
    
    // Secure random generation
    generateSecureToken(length?: number): string;
    generateAPIKey(prefix?: string): string;
    generateNonce(): string;
  }
  
  interface Cipher {
    // Field-level encryption for sensitive data
    encryptField(data: string, key: string): EncryptedField;
    decryptField(encryptedField: EncryptedField, key: string): string;
    
    // File encryption
    encryptFile(filePath: string, outputPath: string, key: string): Promise<void>;
    decryptFile(filePath: string, outputPath: string, key: string): Promise<void>;
  }
}

interface EncryptedField {
  encryptedData: string;
  iv: string;
  authTag: string;
  algorithm: string;
}