@tgtone/logger

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

Features

• ✅ Environment-aware: Respects DEBUG and NODE_ENV variables
• ✅ Browser & Node.js compatible: Works in both environments without polyfills
• ✅ Multiple log levels: debug, info, warn, error
• ✅ Namespace support: Organize logs by module/service
• ✅ Production-safe: Auto-disables debug logs in production
• ✅ 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');           // Only shows if DEBUG=true
info('ℹ️ Important information');        // Always shows
warn('⚠️ Warning message');              // Always shows
error('❌ Error occurred');              // Always shows

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]

Child Loggers

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

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

Configuration

Browser Usage (React/Vue/Svelte with Vite)

IMPORTANT: In browser environments, you MUST pass debug explicitly:

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

// ✅ Correct - pass debug explicitly
const logger = new Logger({
  namespace: 'MyApp',
  debug: import.meta.env.DEV, // Vite variable for development mode
});

// ❌ Wrong - will default to false in browser
const logger = new Logger({ namespace: 'MyApp' });

Why? Browsers don't have access to process.env, so the logger detects the browser environment and requires explicit debug configuration.

Node.js Usage (Backend/NestJS/Express)

In Node.js, environment variables work automatically:

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

// ✅ Auto-detects DEBUG=true or NODE_ENV=development
const logger = new Logger({ namespace: 'AuthService' });

Environment Variables

• DEBUG=true - Enable debug logs (Node.js only)
• NODE_ENV=development - Auto-enable debug logs in development (Node.js only)

Programmatic Config

const logger = new Logger({
  debug: true,              // Force enable debug
  namespace: 'MyService',   // Add namespace prefix
  emojis: true,            // Enable emojis (default: true)
  minLevel: LogLevel.INFO, // Minimum log level to show
});

Log Levels

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

LogLevel.DEBUG  // 🔍 Debug information (only if DEBUG=true)
LogLevel.INFO   // ℹ️ General information
LogLevel.WARN   // ⚠️ Warnings
LogLevel.ERROR  // ❌ Errors

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);
  }
}

JWT Strategy

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

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

const jwtExtractor = (req: Request): string | null => {
  const token = ExtractJwt.fromAuthHeaderAsBearerToken()(req);
  
  if (token) {
    logger.debug('Token found, length:', token.length);
    logger.debug('Token expires:', decodedToken.exp);
  } else {
    logger.debug('No token in request');
  }
  
  return token;
};

API Module Initialization

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

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

JwtModule.registerAsync({
  useFactory: (configService: ConfigService) => {
    const secret = configService.get('JWT_SECRET');
    
    logger.debug('Initializing with secret length:', secret.length);
    logger.debug('Expiration:', configService.get('JWT_EXPIRATION'));
    
    return { secret, signOptions: { expiresIn: '7d' } };
  },
});

Migration from console.log

Before:

if (process.env.DEBUG === 'true') {
  console.log('🔍 Token found:', token);
  console.log('📋 Payload:', payload);
}

After:

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

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

Production Behavior

In production (NODE_ENV=production and no DEBUG=true):

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

Development Behavior

In development (NODE_ENV=development or DEBUG=true):

• ✅ All log levels shown

License

MIT

Author

TGT Technology