pino-console

A WHATWG Console API adapter for Pino loggers that provides full Node.js Console interface compatibility with structured JSON logging.

Quick Start

npm install pino-console pino

import pino from 'pino'
import Console from 'pino-console'

const logger = pino()
const console = new Console(logger)

console.log('Hello, structured logging!')
// Output: {"level":30,"time":1234567890,"pid":1234,"hostname":"host","msg":"Hello, structured logging!"}

Table of Contents

• Installation
• Usage
• API Reference
• TypeScript Support
• Examples
• Performance
• Contributing

Installation

npm install pino-console pino

For pretty development output:

npm install pino-pretty

Usage

Basic Setup

import pino from 'pino'
import Console from 'pino-console'

// Create a Pino logger
const logger = pino({
  level: 'info',
  transport: {
    target: 'pino-pretty' // For development
  }
})

// Create a Console adapter
const console = new Console(logger)

// Use console methods as usual
console.log('Application starting...')
console.info('This is an info message')
console.warn('This is a warning')
console.error('This is an error')

Migration from Standard Console

Replace your console usage:

// Before
console.log('User logged in:', userId)

// After
import { console } from './logger.js' // Your pino-console instance
console.log('User logged in:', userId) // Now outputs structured JSON

Log Level Control

import pino from 'pino'
import Console from 'pino-console'

// Only log warnings and errors
const logger = pino({ level: 'warn' })
const console = new Console(logger)

console.debug('Not logged')  // Filtered out
console.log('Not logged')    // Filtered out
console.warn('Logged')       // Shown
console.error('Logged')      // Shown

Level mapping:

• console.debug() → pino.debug() (level 20)
• console.log()/info() → pino.info() (level 30)
• console.warn() → pino.warn() (level 40)
• console.error() → pino.error() (level 50)

API Reference

Constructor

new Console(logger)

Creates a new Console instance.

• Parameters: logger (Pino Logger) - A Pino logger instance
• Throws: TypeError if logger is invalid
• Returns: Console instance

Core Logging Methods

• console.log(message?, ...optionalParams) - Info level logging
• console.info(message?, ...optionalParams) - Info level logging
• console.warn(message?, ...optionalParams) - Warn level logging
• console.error(message?, ...optionalParams) - Error level logging
• console.debug(message?, ...optionalParams) - Debug level logging

Format Specifiers

All logging methods support standard format specifiers:

| Specifier | Description | Example | |-----------|-------------|---------| | %s | String | console.log('Hello %s', 'world') | | %d, %i | Integer | console.log('Count: %d', 42) | | %o | Object (shallow) | console.log('Data: %o', obj) | | %O | Object (deep) | console.log('Data: %O', obj) | | %% | Literal % | console.log('100%% complete') |

Additional Methods

• Timing: time(label?), timeEnd(label?), timeLog(label?, ...data)
• Counting: count(label?), countReset(label?)
• Grouping: group(...label), groupCollapsed(...label), groupEnd()
• Display: table(tabularData, properties?), dir(obj, options?), dirxml(...data), clear()
• Debugging: assert(value, message?, ...params), trace(message?, ...params)
• Inspector: profile(label?), profileEnd(label?), timeStamp(label?) (no-ops)

TypeScript Support

Full TypeScript support is included:

import pino from 'pino'
import Console from 'pino-console'

const logger = pino({ level: 'info' })
export const console = new Console(logger)

// All methods are fully typed
console.log('Message with %s and %d', 'string', 42)
console.time('operation')
console.table([{ name: 'Alice' }, { name: 'Bob' }])
console.timeEnd('operation')

Examples

See example.mjs for a comprehensive demonstration of all features.

Performance

pino-console includes performance optimizations:

• Level-enabled checks: Disabled log levels have minimal overhead
• Lazy evaluation: Format specifiers only processed when needed
• Structured output: Enables efficient log parsing and analysis

import pino from 'pino'
import Console from 'pino-console'

// Level filtering prevents unnecessary work
const logger = pino({ level: 'warn' })
const console = new Console(logger)

// These have near-zero cost when filtered
console.debug('Debug info', expensiveOperation()) // Skipped entirely
console.info('Info message', largeObject)         // Skipped entirely

// These are processed
console.warn('Warning')  // Processed
console.error('Error')   // Processed

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

License

MIT License - see LICENSE file for details.

Related

• Pino - Super fast, all natural JSON logger
• WHATWG Console Standard - Console API specification
• pino-pretty - Pretty print Pino logs