logger-utiln

A simple logging utility for Node.js applications that writes logs to files with timestamp and level-based filtering.

Features

• 📅 Date and time formatting for log entries
• 📝 Four log levels: info, warn, error and debug
• 🔍 Level-based filtering (include only certain log levels)
• 📂 Automatic directory creation for log files
• ⚙️ Configurable log file naming (daily files or custom path)

Installation

npm install logger-utiln

Usage

const { Logger } = require('./logger');

// Initialize logger
const logger = new Logger(
  true,           // enabled
  './logs/app.log', // log file path
  ['debug', 'info'] // log levels to record
);

// Log messages
logger.info('Application started');
logger.warn('Low memory warning');
logger.error('Critical failure', 500);

API Reference

new Logger(enabled, link, level)

Creates a new Logger instance.

Parameters:

• enabled (Boolean): Enable/disable logging
• link (String): Path to log file/directory
• level (String|Array): Log level(s) to record ('debug', 'info', 'warn', 'error')

Logging Methods

• .info(msg, code = 0)
• .warn(msg, code = 1)
• .error(msg, code = -1)

Each method writes a formatted log entry if the logger is enabled and the level matches.

Log File Behavior

• If path ends with a filename (e.g., app.log), all logs go to that file
• If path is a directory, creates daily log files (YYYY-MM-DD.log)
• Automatically creates parent directories if they don't exist

Example Output

2023-05-20 14:30:45 INFO: Application started [0]
2023-05-20 14:31:10 WARN: Low memory warning [1]
2023-05-20 14:32:00 ERROR: Critical failure [-1]

License

MIT