@calphonse/logger

A beautiful, intelligent logger for Node.js with AI-powered error analysis

Features

• Beautiful colored output with timestamps and file locations
• AI-powered error analysis with intelligent insights and fix suggestions
• Structured JSON logging for production environments
• Security hardened with input validation and sanitization
• TypeScript first with full type safety
• Zero dependencies for core functionality (AI features optional)

Installation

npm install @calphonse/logger

Quick Start

import { logger } from '@calphonse/logger';


logger.info('Application started');
logger.warn('High memory usage detected');
logger.error('Database connection failed', { error: 'Connection timeout' });


logger.info('User login', {
  userId: '12345',
  method: 'email',
  timestamp: new Date().toISOString(),
});


try {
  throw new Error('Invalid JWT token');
} catch (error) {
  logger.error('Auth failed', error);
}

AI-Powered Analysis

Errors automatically get intelligent analysis:

logger.error('Database error', new Error('Connection refused'));

// Output includes AI insights:
// AI Insight: Database connection failed
// Likely Causes: Service down, network issues, wrong credentials
// Suggested Fix: Check database service status and connection string

Setup AI (Optional)

curl -fsSL https://ollama.ai/install.sh | sh
ollama pull llama3.2:3b

# Or use cloud providers (OpenAI, Claude)
# Set environment variables: OPENAI_API_KEY, etc.

Configuration

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

const logger = new Logger({
  level: LogLevel.INFO,
  colors: true,
  timestamps: true,
  showSource: true,
  prefix: '[MY-APP]',
  json: false, // Set to true for production
  ai: {
    enabled: true,
    provider: 'ollama', // 'openai' | 'claude' | 'disabled'
    caching: true,
  },
});

Factory Methods

import { LoggerFactory } from '@calphonse/logger';

const jsonLogger = LoggerFactory.createJsonLogger();
const minimalLogger = LoggerFactory.createMinimalLogger();
const verboseLogger = LoggerFactory.createVerboseLogger();

Child Loggers

const userLogger = logger.child('[USER]');
const dbLogger = logger.child('[DB]');

userLogger.info('User created', { userId: '123' });
dbLogger.error('Query failed', { query: 'SELECT * FROM users' });

API Reference

Core Methods

logger.error(message: string, data?: any): void
logger.warn(message: string, data?: any): void
logger.info(message: string, data?: any): void
logger.debug(message: string, data?: any): void
logger.trace(message: string, data?: any): void

logger.table(data: any[]): void
logger.child(prefix: string): Logger
logger.setLevel(level: LogLevel): void

Log Levels

enum LogLevel {
  ERROR = 0, // Only errors
  WARN = 1, // Warnings and errors
  INFO = 2, // Info, warnings, and errors (default)
  DEBUG = 3, // Debug and above
  TRACE = 4, // Everything
}

Express.js Example

import express from 'express';
import { logger } from '@calphonse/logger';

const app = express();


app.use((req, res, next) => {
  logger.info('Request', {
    method: req.method,
    url: req.url,
    userAgent: req.get('User-Agent'),
  });
  next();
});


app.use((err, req, res, next) => {
  logger.error('Request failed', err);
  res.status(500).json({ error: 'Internal server error' });
});

License

MIT License - see LICENSE file for details.

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Made with care for the Node.js community

If this logger helps you debug faster, please give it a star on GitHub!