@tgtone/logger

Debug logger utility for TGT One projects with environment-based control

Features

• ✅ Environment-aware: Control via VITE_LOG_LEVELS (browser) or LOG_LEVELS (Node.js)
• ✅ Browser & Node.js compatible: Works in both environments without polyfills
• ✅ Multiple log levels: debug, info, warn, error
• ✅ Namespace support: Organize logs by module/service
• ✅ Child loggers: Create nested loggers that inherit configuration
• ✅ Timestamp support: Optional ISO timestamp in each log
• ✅ Production-safe: Control exactly which levels to show
• ✅ Zero dependencies: Lightweight and fast
• ✅ TypeScript: Fully typed
• ✅ Vite-ready: No define config needed

Installation

npm install @tgtone/logger

Quick Start

Basic Usage

import { debug, info, warn, error } from '@tgtone/logger';

debug('🐛 Debug information');           // Shows if 'debug' in VITE_LOG_LEVELS
info('ℹ️ Important information');        // Shows if 'info' in VITE_LOG_LEVELS
warn('⚠️ Warning message');              // Shows if 'warn' in VITE_LOG_LEVELS
error('❌ Error occurred');              // Shows if 'error' in VITE_LOG_LEVELS

With Namespace

import { Logger } from '@tgtone/logger';

const logger = new Logger({ namespace: 'AuthService' });

logger.debug('Token validation started');
// 🐛 [AuthService] Token validation started

logger.info('User logged in:', user.email);
// ℹ️ [AuthService] User logged in: [email protected]

With Timestamp

import { Logger } from '@tgtone/logger';

const logger = new Logger({ namespace: 'API', timestamp: true });

logger.debug('Request received');
// [2024-01-15T10:30:00.000Z] 🐛 [API] Request received

Child Loggers

const authLogger = new Logger({ namespace: 'Auth' });
const jwtLogger = authLogger.child('JWT');

jwtLogger.debug('Verifying token');
// 🐛 [Auth:JWT] Verifying token

Configuration

Environment Variables

Control log levels via environment variables:

| Variable | Environment | Example | |----------|-------------|---------| | VITE_LOG_LEVELS | Browser (Vite) | VITE_LOG_LEVELS=debug,info | | LOG_LEVELS | Node.js | LOG_LEVELS=warn,error |

Log Level Values

| Valor | Resultado | |-------|-----------| | * o no definido | Todos los niveles habilitados | | debug,info,warn | Solo debug, info y warn | | error | Solo errores | | none | Deshabilita todos los niveles |

Browser Usage (React/Vue/Svelte with Vite)

# .env.local
VITE_LOG_LEVELS=*           # Todos los niveles (desarrollo)
VITE_LOG_LEVELS=error       # Solo errores (producción)
VITE_LOG_LEVELS=debug,info  # Solo debug e info

import { Logger } from '@tgtone/logger';

// El logger lee automáticamente VITE_LOG_LEVELS
const logger = new Logger({ namespace: 'MyApp' });

logger.debug('This shows if debug is enabled');

Node.js Usage (Backend/NestJS/Express)

# Development
LOG_LEVELS=* npm run start

# Production
LOG_LEVELS=error npm run start:prod

import { Logger } from '@tgtone/logger';

// El logger lee automáticamente LOG_LEVELS
const logger = new Logger({ namespace: 'AuthService' });

Programmatic Config

import { Logger, LogLevel } from '@tgtone/logger';

const logger = new Logger({
  namespace: 'MyService',     // Add namespace prefix
  emojis: true,               // Enable emojis (default: true)
  timestamp: true,            // Show ISO timestamp (default: false)
  minLevel: LogLevel.INFO,    // Minimum log level (fallback)
  allowedLevels: [LogLevel.DEBUG, LogLevel.INFO], // Specific levels
});

Log Levels

import { LogLevel } from '@tgtone/logger';

LogLevel.DEBUG  // 🐛 Debug information
LogLevel.INFO   // ℹ️ General information
LogLevel.WARN   // ⚠️ Warnings
LogLevel.ERROR  // ❌ Errors
LogLevel.NONE   // 🚫 Disable all logs

API Reference

Logger

class Logger {
  constructor(config?: LoggerConfig)
  
  debug(...args: any[]): void
  info(...args: any[]): void
  warn(...args: any[]): void
  error(...args: any[]): void
  
  child(namespace: string): Logger
  isDebugEnabled(): boolean
}

LoggerConfig

interface LoggerConfig {
  namespace?: string;           // Prefix for all logs
  emojis?: boolean;             // Show emojis (default: true)
  timestamp?: boolean;          // Show ISO timestamp (default: false)
  minLevel?: LogLevel;          // Minimum level (default: DEBUG)
  allowedLevels?: LogLevel[];   // Specific allowed levels
}

Helper Functions

import { debug, info, warn, error, defaultLogger } from '@tgtone/logger';

// Use default logger directly
debug('Message');
info('Message');
warn('Message');
error('Message');

// Or access the default logger instance
defaultLogger.debug('Message');

Use Cases

NestJS Services

import { Logger } from '@tgtone/logger';

export class AuthService {
  private logger = new Logger({ namespace: 'AuthService' });

  async login(email: string, password: string) {
    this.logger.debug('Login attempt:', email);
    
    // ... authentication logic
    
    this.logger.info('User logged in:', email);
  }
}

React Components

import { Logger } from '@tgtone/logger';

const logger = new Logger({ namespace: 'useAuth' });

export function useAuth() {
  const login = async (email: string) => {
    logger.debug('Login attempt:', email);
    // ...
  };
  
  return { login };
}

API Client

import { Logger } from '@tgtone/logger';

const logger = new Logger({ namespace: 'API', timestamp: true });

async function fetchData(url: string) {
  logger.debug('Fetching:', url);
  
  try {
    const response = await fetch(url);
    logger.info('Response:', response.status);
    return response;
  } catch (error) {
    logger.error('Fetch failed:', error);
    throw error;
  }
}

Migration from console.log

Before:

console.log('🔍 Token found:', token);
console.log('📋 Payload:', payload);

After:

import { debug } from '@tgtone/logger';

debug('Token found:', token);
debug('Payload:', payload);

Production Behavior

With VITE_LOG_LEVELS=error or LOG_LEVELS=error:

• ✅ error() → shown
• ❌ debug(), info(), warn() → suppressed

Development Behavior

With VITE_LOG_LEVELS=* or not defined:

• ✅ All log levels shown

Changelog

1.2.0

• ✨ Added timestamp option for ISO timestamp in logs
• ✨ Added LOG_LEVEL_PRIORITY for level hierarchy
• 🐛 Fixed child() to properly pass allowedLevels
• 🐛 Fixed isDebugEnabled() to be consistent with shouldLog()
• 🔥 Removed deprecated debugEnabled property
• 🎨 Changed debug emoji from 🔍 to 🐛

1.1.0

• Initial release with VITE_LOG_LEVELS support

License

MIT

Author

TGT Technology