@laziest/logger

Small logger for browser and Node.js libraries and applications.

Install

pnpm add @laziest/logger

Quick Start

import { consoleTransport, createLogger } from '@laziest/logger'

const logger = createLogger({
  name: 'app',
  level: 'debug',
  transports: [consoleTransport({ format: 'pretty' })],
})

logger.info('App started', { port: 3000 })
logger.child('loader').debug('Loaded resource', { url: '/hero.png' })

Formats

Pretty

[12:30:21.123] INFO   app:loader  Loaded resource
url=/hero.png

Compact

12:30:21.123 info app:loader Loaded resource url=/hero.png

JSON

{"time":"2026-05-19T04:30:21.123Z","level":"info","name":"app","scope":["loader"],"message":"Loaded resource","context":{"url":"/hero.png"}}

Application Setup

Use an explicit level and a console transport for local development.

const logger = createLogger({
  name: 'app',
  level: 'debug',
  transports: [consoleTransport({ format: 'pretty' })],
})

Library Defaults

The logger defaults to silent, so libraries can accept user-provided logger options without writing to the console by default.

const logger = createLogger({
  name: 'my-library',
  transports: [consoleTransport()],
})

logger.info('Hidden until level is enabled')

Multiple Transports

import { consoleTransport, createLogger, memoryTransport } from '@laziest/logger'

const records = []
const logger = createLogger({
  level: 'info',
  transports: [
    consoleTransport({ format: 'compact' }),
    memoryTransport(records),
  ],
})

Child Loggers

const logger = createLogger({
  name: 'app',
  level: 'info',
  transports: [consoleTransport({ format: 'compact' })],
})

const loaderLogger = logger.child('loader')

loaderLogger.info('Loaded resource', { url: '/hero.png' })

Errors

Prefer logging errors as context:

logger.error('Request failed', { err })