Logger

中文 | English

A lightweight log management tool that supports different log levels and modular management.

Features

• Support setting log names for modular log management
• Support multiple log levels: trace, debug, info, warn, error, fatal
• Lightweight design with zero dependencies
• Complete TypeScript type support

Installation

Install using npm:

npm install @lib-stack/logger

Basic Usage

Using the Default Exported logger Instance

import { logger } from '@lib-stack/logger'

// Set log level
logger.setLevel('info')
// Print logs of different levels
logger.debug('This is a debug log') // Will not be output because level is lower than info
logger.error('This is an error log')

Managing Multiple Log Instances with get Method

import { logger } from '@lib-stack/logger'

// Get or create named log instances
const apiLogger = logger.get('api')
const dbLogger = logger.get('database')

Creating Custom Log Instances

import { createLogger } from '@lib-stack/logger'

// Create default log instance
const logger = createLogger()

API Reference

createLogger(options?: LoggerOptions): Logger

Creates a new log instance.

Parameters

• options: Optional configuration object
  • name: Log name, used to identify different log instances

Return Value

• Returns a log object with the following methods:
  • trace(...args: unknown[]): Print trace logs
  • debug(...args: unknown[]): Print debug logs
  • info(...args: unknown[]): Print info logs
  • warn(...args: unknown[]): Print warning logs
  • error(...args: unknown[]): Print error logs
  • fatal(...args: unknown[]): Print fatal error logs
  • setLevel(level: LogLevel): Set log level
  • getLevel(): LogLevel: Get current log level
  • get(name?: string, options?: Extract<LoggerOptions, 'name'>): Logger: Get or create named log instances
  • getAll(): Logger[]: Get all created log instances

Log Levels

Available log levels (from lowest to highest severity):

• trace: Most detailed logs, usually for development debugging
• debug: Debug information logs
• info: General information logs
• warn: Warning information that doesn't affect program operation
• error: Error information that may affect some functions
• fatal: Fatal error information, program may not continue running
• off: Turn off all log output

Advanced Usage

Modular Log Management

// File: src/api.ts
import { logger } from '@lib-stack/logger'

const apiLogger = logger.get('api')
apiLogger.info('API request started')

// File: src/database.ts
import { logger } from '@lib-stack/logger'

const dbLogger = logger.get('database')
dbLogger.debug('Executing SQL query')

Configuring Different Log Levels for Different Environments

import { logger } from '@lib-stack/logger'

if (process.env.NODE_ENV === 'development') {
  logger.setLevel('debug')
}
else {
  logger.setLevel('error')
}

License

This project is licensed under the MIT License. For details, see the LICENSE file.