@dmitryrechkin/eslint-standard

A comprehensive ESLint configuration package with TypeScript support, featuring Prettier integration with Allman brace style and industry-standard rules for maximum code quality.

🚀 Quick Start

Installation

npm install -D @dmitryrechkin/eslint-standard
npx @dmitryrechkin/eslint-standard install-deps

Basic Usage

// eslint.config.mjs
import config from '@dmitryrechkin/eslint-standard';

export default config({
	tsconfigPath: './tsconfig.json'
});

📋 Available Presets

Standard (Default)

Balanced configuration suitable for most projects.

import config from '@dmitryrechkin/eslint-standard';
export default config();

Aggressive

Enhanced unused code detection for maximum code quality.

import config from '@dmitryrechkin/eslint-standard/aggressive';
export default config();

Features:

• ✅ Enhanced unused variable detection
• ✅ Import/export cleanup
• ✅ Dead code detection (unreachable code)
• ✅ Strict unused expressions rules
• ✅ TypeScript-specific cleanup

Library

Optimized for TypeScript libraries with strict API requirements.

import config from '@dmitryrechkin/eslint-standard/library';
export default config();

Features:

• ✅ Very strict unused exports detection
• ✅ API documentation requirements (JSDoc)
• ✅ Explicit return types
• ✅ No console/debugging code
• ✅ Enhanced type safety rules

Strict Mode

Enterprise-grade architectural conventions for large-scale TypeScript monorepos. Enforces consistent project structure, naming conventions, and design patterns.

import config from '@dmitryrechkin/eslint-standard';

export default config({
	strict: true,
	tsconfigPath: './tsconfig.json'
});

Features:

• ✅ Enforced folder structure (services/, repositories/, helpers/, etc.)
• ✅ Single Responsibility Principle for services and transformers
• ✅ CQRS pattern enforcement for repositories
• ✅ Static-only helpers, no static methods in other classes
• ✅ Consistent interface naming conventions
• ✅ One class per file

Strict Mode Rules

| Rule | Enforcement | Rationale | |------|-------------|-----------| | Class Location | *Service → services/, *Repository → repositories/, *Helper → helpers/, *Factory → factories/, *Transformer → transformers/, *Registry → registries/, *Adapter → adapters/ | Predictable project structure enables faster navigation and onboarding | | Service Single Method | Services must have only one public method | Single Responsibility Principle - each service does one thing well | | Transformer Single Method | Transformers must have only one public method | Clear data transformation contracts | | Helper Static Only | Helper classes must contain only static methods | Helpers are utility collections, not stateful objects | | No Static in Non-Helpers | Non-helper/factory classes cannot have static methods | Prevents hidden global state, improves testability via dependency injection | | Type Location | interface TypeXXX must be in types/ folder | Centralized type definitions for reusability | | Interface Naming | TypeXXX for data types, XXXInterface for class contracts | Clear distinction between data structures and behavioral contracts | | One Class Per File | Each file can contain only one class | Simplifies imports, improves code organization | | Repository CQRS | CommandRepository cannot have query methods (get, find, list), QueryRepository cannot have command methods (create, update, delete) | Command Query Responsibility Segregation for scalable data access | | Folder CamelCase | All folder names must be camelCase | Consistent naming across the codebase | | Function Name Match Filename | Top-level function name must match filename | Predictable imports and file discovery | | No Utils Folder | utils/ folder is forbidden | Use helpers/ for stateless logic or domain objects for stateful logic |

Example Project Structure

src/
├── services/
│   ├── UserService.ts          # class UserService { execute() }
│   └── PaymentService.ts       # class PaymentService { process() }
├── repositories/
│   ├── UserCommandRepository.ts # create(), update(), delete()
│   └── UserQueryRepository.ts   # find(), getById(), list()
├── helpers/
│   └── ValidationHelper.ts      # static validate(), static sanitize()
├── factories/
│   └── UserFactory.ts           # static create()
├── transformers/
│   └── UserTransformer.ts       # transform()
├── types/
│   ├── TypeUser.ts              # interface TypeUser { id: string }
│   └── TypePayment.ts           # interface TypePayment { amount: number }
└── adapters/
    └── StripeAdapter.ts         # class StripeAdapter

⚙️ Configuration Options

All configurations accept the same configuration options:

export default config({
	tsconfigPath: './tsconfig.json',    // Path to TypeScript config
	ignores: ['build/**', 'dist/**'],   // Additional ignore patterns
	files: ['src/**/*'],                // File patterns to lint
	rules: {                           // Rule overrides
		'no-console': 'warn'
	}
});

🛠️ CLI Commands

The package includes a CLI for dependency management:

# Install all peer dependencies
npx @dmitryrechkin/eslint-standard install-deps

# Check if dependencies are installed
npx @dmitryrechkin/eslint-standard check-deps

# Auto-install missing dependencies
npx @dmitryrechkin/eslint-standard check-deps --install

🎯 Rule Categories

Code Quality & Safety

• Type Safety: Strict TypeScript rules, ban any type
• Error Prevention: Catch common bugs and unsafe patterns
• Security: Prevent common security vulnerabilities
• Performance: Avoid performance anti-patterns

Code Style & Formatting

• Prettier Integration: Automatic code formatting with industry-standard plugins
• Brace Style: Allman style (braces on new lines) via prettier-plugin-brace-style
• Indentation: Tabs (4-space width) for accessibility and user preference
• Quotes: Single quotes for consistency
• Import Organization: Automatic import sorting and grouping
• JSDoc: Required documentation with proper alignment and formatting

Code Complexity & Architecture

• Function Complexity: Max 10 cyclomatic complexity (industry standard)
• Cognitive Complexity: Max 15 (SonarJS) for maintainable code
• Function Length: Max 100 lines (300 for tests) following clean code principles
• File Length: Max 300 lines (500 for tests) for focused modules
• Function Parameters: Max 7 parameters (allows dependency injection patterns)
• Nesting Depth: Max 3 levels to prevent callback hell

Modern JavaScript/TypeScript

• ES2020+ Features: Prefer modern syntax and APIs
• Functional Programming: Pragmatic immutability patterns
• Promise Handling: Proper async/await usage
• Import/Export: Clean module system usage

📊 Preset Comparison

| Feature | Standard | Aggressive | Library | Strict Mode | |---------|----------|------------|---------|-------------| | Unused imports cleanup | ✅ | ✅ | ✅ | ✅ | | Unused variables detection | Basic | Enhanced | Enhanced | Basic | | Dead code detection | Basic | ✅ | ✅ | Basic | | Unused exports check | ❌ | ✅ | Very Strict | ❌ | | JSDoc requirements | Basic | Basic | Strict | Basic | | Console statements | Warning | Warning | Error | Warning | | Return type hints | Error | Error | Explicit | Error | | Type safety | High | High | Very High | High | | Folder structure enforcement | ❌ | ❌ | ❌ | ✅ | | Single Responsibility (Services) | ❌ | ❌ | ❌ | ✅ | | CQRS Repository pattern | ❌ | ❌ | ❌ | ✅ | | Interface naming conventions | ❌ | ❌ | ❌ | ✅ | | One class per file | ❌ | ❌ | ❌ | ✅ | | Static method restrictions | ❌ | ❌ | ❌ | ✅ |

📈 Industry Standards Comparison

| Metric | This Package | Google | Airbnb | SonarQube | Clean Code | |--------|--------------|--------|---------|-----------|------------| | Max Parameters | 7 | 4 | No limit* | 7 | 3-4 | | Max Function Lines | 100 | 50 | No limit | 200 | 20 | | Max File Lines | 300 | 2000 | 2500 | 1000 | 300 | | Cyclomatic Complexity | 10 | 10 | No limit | 10 | 5-10 | | Max Nesting | 3 levels | 3 levels | No limit | 3 levels | 2-3 levels | | Brace Style | Allman | 1TBS | 1TBS | Configurable | Any | | Indentation | Tabs (4) | Spaces (2) | Spaces (2) | Configurable | Spaces (4) |

*Airbnb recommends objects for >3 parameters

🎨 Prettier Integration Features

This package includes seamless Prettier integration that handles all formatting automatically:

Supported File Types

• TypeScript/JavaScript: .ts, .js, .tsx, .jsx with Allman brace style
• Astro: .astro files with optimized formatting via prettier-plugin-astro

Automatic Formatting

• Allman Brace Style: All braces on new lines for maximum readability
• Single Quotes: Consistent string quoting throughout codebase
• Tab Indentation: Accessible indentation with 4-space tab width
• Semicolons: Always required for statement clarity
• No Trailing Commas: Clean object/array formatting

ESLint-Prettier Harmony

• All conflicting ESLint formatting rules are automatically disabled
• Prettier handles formatting, ESLint handles code quality
• No configuration conflicts - works out of the box

🔧 External Tools Integration

For comprehensive unused code detection, consider these additional tools:

# Find unused exports
npx ts-prune

# Find unused files  
npx unimported

# Advanced dead code analysis
npx knip

# Find unused dependencies
npx depcheck

🚦 Usage Recommendations

For Applications

Use Standard preset - provides good balance of strictness and practicality.

For Libraries

Use Library preset - ensures clean public APIs and comprehensive documentation.

For Maximum Code Quality

Use Aggressive preset - comprehensive unused code detection.

For Enterprise Monorepos

Use Strict Mode - enforces architectural conventions, folder structure, and design patterns for large teams.

🔍 Example Projects

React Application

// eslint.config.mjs
import config from '@dmitryrechkin/eslint-standard';

export default config({
	tsconfigPath: './tsconfig.json',
	ignores: ['dist/**', 'build/**', 'public/**']
});

TypeScript Library

// eslint.config.mjs
import config from '@dmitryrechkin/eslint-standard/library';

export default config({
	tsconfigPath: './tsconfig.json',
	ignores: ['dist/**', 'examples/**']
});

Node.js API

// eslint.config.mjs
import config from '@dmitryrechkin/eslint-standard/aggressive';

export default config({
	tsconfigPath: './tsconfig.json',
	rules: {
		'no-console': 'off', // Allow console in Node.js
	}
});

Enterprise Monorepo

// eslint.config.mjs
import config from '@dmitryrechkin/eslint-standard';

export default config({
	strict: true,
	tsconfigPath: './tsconfig.json',
	ignores: ['dist/**', 'node_modules/**']
});

🤝 Contributing

Issues and pull requests are welcome on GitHub.

📄 License

MIT License - see LICENSE file for details.