🛠️ Custom Logger for Node.js

A lightweight, powerful, and flexible logging utility for Node.js applications. Simple to integrate and use without extra boilerplate code. Supports console and file logging with daily rotation, user-configurable 12 or 24-hour timestamp format, formatted timestamps, log levels, automatic log cleanup, an Express request/response watchman, and more.

✨ Features That Developers Love

• ✨ Lightweight and Simple: Easy to configure and use with sensible defaults.
• ✅ Console Logging with colorful prefixes
• 🗂️ File Logging with daily rotation and size-based backups
• 🧠 Supports 8 log levels:
  • DEBUG, INFO, SUCCESS, WARN, ERROR, FATAL, HTTP, and CUSTOM
• ⏱️ Configurable Time Format: Choose between 12-hour or 24-hour timestamp display.
• 🧾 Format Options: plain or json
• 🧭 Timezone-aware timestamps (IST, UTC, etc.)
• 📦 Auto-creates /logs directory for you
• ♻️ Auto-delete old log files based on backups count
• 🎨 Color-coded outputs (like cyan for debug, red for error)
• 🕵️ Express Watchman: Automatically log incoming requests and outgoing responses for Express apps (console & file).
• 🧩 Pluggable architecture (remote logging coming soon!)

📦 Installation

npm install rg-epic-logger

🚀 Getting Started

💻 Console Logger Example

const Logger = require('rg-epic-logger').default;

const logger = new Logger({
    level: 'DEBUG',
    format: 'plain',
    console: true,
    consolePrefix: 'App',
    timezone: 'IST'
});

logger.debug('Debugging started...');
logger.success('Operation completed successfully!');
logger.warn('Something might be wrong...');
logger.error('An error occurred!');
logger.info('This is some information.');

🕵️ Express Watchman Example (Easy Setup!)

Automatically log incoming requests and outgoing responses for your Express server with minimal setup. Initialize the logger, ensuring watch: true (which is the default). The logger will then automatically monitor Express activity for you.

const Logger = require('rg-epic-logger').default;
const express = require('express'); // Make sure Express is required somewhere in your project

const app = express();
const port = 3000;

// Initialize Logger with Watchman enabled
// Setting watch: true automatically activates request/response logging
// for Express applications running in this process.
const logger = new Logger({
    level: 'DEBUG',
    format: 'plain',
    watch: true,           // <<< Setting this to true enables AND activates the watchman
    watchPrefix: 'Watch',  // <<< Customize the prefix for watched logs
    timezone: 'IST'
});

// --- NO explicit middleware setup needed! ---
// If 'watch: true', the logger monitors Express automatically.

// Example route
app.get('/', (req, res) => {
    // Regular logs still work using 'consolePrefix' (default 'Application')
    // logger.info('Handling GET / request');
    res.send('Hello World!');
    // Request ('/') and Response ('Hello World!') details will be automatically
    // logged by the watchman using the 'Watch' prefix.
});

app.listen(port, () => {
    logger.success(`Server listening on port ${port}`); // Regular log
});

🗂️ File Logger with Daily Rotation and Auto-Backup

const Logger = require('rg-epic-logger').default;

const logger = new Logger({
    level: 'INFO',
    format: 'plain',
    fileRotate: true,
    fileFormat: 'DD-MM-YYYY',
    fileBackups: 2,  // keep only last 2 days log files
    fileSize: 10,   // max file size in MB before rotating
    timezone: 'IST',
    use24Hour: true // Explicitly set for clarity (default is true)
});

logger.info('Logging to file with daily rotation.');

📁 Logs are stored in /logs and named like:

logs/
├── Application/              # Regular logs (from logger.info, etc.)
│   ├── 15-04-2025.log
│   └── 14-04-2025.log        # Example previous day's log
└── Global/                   # Watched request/response logs
    ├── 15-04-2025.log
    └── 14-04-2025.log        # Example previous day's log

After reaching the fileBackups limit (e.g. 2), older logs will be automatically deleted.

🔥 Full List of Log Levels

⚙️ Configuration Options

📅 File Format & Cleanup Behavior

🗂 fileFormat Options

This allows you to organize logs by day or by hour, especially useful for high-frequency logging systems.

💾 fileSize

• Controls maximum file size (in MB) before rotation.
• Example: fileSize: 10 will rotate when the log file exceeds 10 MB.
• Once a log file hits the size limit, it's archived, and a new one is created automatically.

Older logs are cleaned up based on the fileBackups limit.

📁 Log File Structure with Watchman Enabled

When both fileRotate: true and watch: true are enabled, logs are automatically separated into directories based on their prefixes:

- **Regular Logs**: Use the consolePrefix (Default: Application)
- **Watched Logs**: Use the watchPrefix (Default: Global)

Example structure with fileFormat: 'DD-MM-YYYY' (Assuming today is April 15, 2025):

logs/
├── Application/         # Regular logs via logger.info(), .debug(), etc.
│   ├── 15-04-2025.log   # Current log file
│   └── 14-04-2025.log   # Previous day's log (kept based on fileBackups)
└── Global/              # Watched request/response logs via logger.watchman()
    ├── 15-04-2025.log   # Current log file
    └── 14-04-2025.log   # Previous day's log (kept based on fileBackups)

• Example structure with fileFormat: 'DD-MM-YYYY/HH' (Assuming current time is 14:xx on April 15, 2025):

logs/
├── Application/
│   └── 15-04-2025/
│       ├── 14.log       # Current hour's log file
│       └── 13.log       # Previous hour's log (kept based on fileBackups)
└── Global/
    └── 15-04-2025/
        ├── 14.log       # Current hour's log file
        └── 13.log       # Previous hour's log (kept based on fileBackups)

Important:

1. The /logs directory and prefix subdirectories (Application, Global) are created automatically if they don't exist.
2. Cleanup: The fileBackups limit applies independently to each log prefix directory. With fileBackups: 2, the logger will keep the latest 2 log files/folders for Application and the latest 2 for Global. Older ones for each prefix are deleted.

⚡ Tip: Benchmark Your Logs

for (let i = 0; i < 10000; i++) {
    logger.info(`Log entry #${i}`);
}

Great for performance/load testing!

🚧 Coming Soon

I'm actively working on adding more powerful features to make this logger even more epic:

• ☁️ Remote Logging Support (Log to a remote server or cloud storage)
• 📊 Web Dashboard (View, search, and filter logs in real-time)
• 📬 Email & Slack Alerts for ERROR or FATAL logs
• 🧪 Unit Tests for rock-solid reliability
• 🔐 Encrypted Log Files for sensitive environments
• ⏳ Async Logging Queue to avoid I/O blocking
• 🧰 CLI Tool to tail and search logs from the terminal

Have a feature in mind?
📩 Please email at gondaliya.ronak100@gmail.com

🧑‍💻 Author

Made with ❤️ by [Ronak Gondaliya]
📨 Contact