@guiiai/logg

Logg

Yet another simple, nearly zero dependency, structural log compliance logger implementation.

Features

• Stack Parse: Automatically captures and includes stack trace information for enhanced debugging.
• Caller Records: Provides detailed information about the calling function and file.
• JSON Format & stdout: Outputs logs in JSON format to stdout for easy parsing and integration with log management tools.
• Drop-in Replacement for Winston: Can be used as a direct replacement for the popular Winston logger.
• Best Practices for Structural Logging: Implements industry best practices for structured logging.
• Intuitive API: Simple and easy-to-use API for quick integration into your projects.

Installation

npm install logg

Usage

const { createLogg } = require('logg');

// Create a logger instance with a specific context
const log = createLogg('http/request').useGlobalConfig();

// Log a 404 error with additional fields
log
  .withField('requestId', req.id)
  .withField('url', req.url)
  .error('Resource not found (404)');

API

Creating a Logger

• createLogg(context: string): Creates a new logger instance with the specified context.

Logger Configuration

• useGlobalConfig(): Applies global configuration to the logger instance.
• child(fields?: Record<string, any>): Creates a child logger with additional fields.
• withContext(context: string): Sets the context dynamically. Returns a cloned logger instance.
• withLogLevel(logLevel: LogLevel): Sets the log level dynamically. Returns a cloned logger instance.
• withLogLevelString(logLevelString: LogLevelString): Sets the log level dynamically using string. Returns a cloned logger instance.
• withFormat(format: Format): Sets the format dynamically. Returns a cloned logger instance.
• withFields(fields: Record<string, any>): Alias for child().
• withField(key: string, value: any): Adds a single custom field to the log entry.
• withError(err: Error | unknown): Attaches an error object to the log entry.

Logging Methods

• debug(message: any, ...optionalParams: [...any, string?]): Logs a debug message.
• verbose(message: any, ...optionalParams: [...any, string?]): Logs a verbose message.
• log(message: any, ...optionalParams: any[]): Logs a general message.
• error(message: any, stack?: string, ...optionalParams: any[]): Logs an error message.
• errorWithError(message: any, err: Error | unknown, ...optionalParams: any[]): Logs an error message with an error object.
• warn(message: any, ...optionalParams: [...any, string?]): Logs a warning message.

Global Configuration Functions

• getGlobalLogLevel(): Retrieves the global log level.
• setGlobalLogLevel(logLevel: LogLevel): Sets the global log level.
• getGlobalLogLevelString(): Retrieves the global log level as a string.
• setGlobalLogLevelString(logLevelString: LogLevelString): Sets the global log level using a string.
• getGlobalFormat(): Retrieves the global format.
• setGlobalFormat(format: Format): Sets the global format.

Enums

• LogLevel: Enum for log levels (Error, Warning, Log, Verbose, Debug).
• LogLevelString: Enum for log level strings (error, warn, log, verbose, debug).
• Format: Enum for log formats (JSON, Pretty).