TSClassLogger

Simple, modern logger for TypeScript classes with formatting and colors.

Installation

npm install ts-class-logger

Quick Start

import { Logger } from "ts-class-logger";

const logger = new Logger("MyClass");

logger.debug("Debug message");
logger.info("Info message", { data: 123 });
logger.warn("Warning!");
logger.error("Error", new Error("something failed"));

Features

• No double-invoke - Just logger.debug("msg"), not logger.debug("msg")()
• Log levels - TRACE, DEBUG, INFO, LOG, WARN, ERROR, OFF
• Formatted output - Customizable format strings with timestamps
• Colors - ANSI colors in Node.js, CSS styling in browsers
• Callbacks - Hook into log events for external services
• Environment detection - Auto-detects Node.js vs browser

Configuration

import { Logger, Level, LoggerOptions } from "ts-class-logger";

const options: LoggerOptions = {
  level: Level.DEBUG,                    // Minimum level to log
  format: "[{timestamp}] {level} [{name}]: {message}",
  timestampFormat: "ISO",                // "ISO" | "locale" | custom function
  colors: "auto",                        // true | false | "auto"
  logToConsole: true,                    // Set false to only use callbacks

  // Callbacks
  onDebug: (args) => { /* ... */ },
  onAny: (level, args) => { /* send to logging service */ },
};

const logger = new Logger("MyClass", options);

Using with Classes

Use this.constructor.name for automatic class name detection:

class MyService {
  private logger = new Logger(this.constructor.name);

  doWork() {
    this.logger.info("Processing...");
    // Output: [2024-01-15T10:30:00Z] INFO [MyService]: Processing...
  }
}

Format Tokens

• {timestamp} - Formatted timestamp
• {level} - Log level (DEBUG, INFO, etc.)
• {name} - Logger name
• {message} - Log arguments

Log Levels

From lowest to highest priority:

1. Level.TRACE - Verbose debugging
2. Level.DEBUG - Debug information
3. Level.INFO - General information
4. Level.LOG - Standard logs
5. Level.WARN - Warnings
6. Level.ERROR - Errors
7. Level.OFF - Disable all logging

Migration from v1

Breaking changes in v2:

| v1 | v2 | |----|-----| | logger.debug("msg")() | logger.debug("msg") | | options.debug callback | options.onDebug | | forceConsoleLog option | Removed |

License

ISC