Simple-json-logger NPM

Simple JSON Logger

Easy to use
All are JSON

Install

npm install --save simple-json-logger

Usage

Basic Usage

You can log any number strings, objects or errors in any order. Logger will classify them and put them into right fields.

const logger = require('simple-json-logger')

logger.log('hello world')
// {"level": 30, "message": "hello world"}

logger.warn('some user is invalid', {name: 'Bob', age: 20})
// {"level": 40, "message": "some user is invalid", "detail": {"name": "Bob", "age": 20}}

logger.error('Something', new TypeError('invalid arg'), 'Wrong!!!')
// {"level": 50, messages:['Something', 'Wrong!!!'], "error": {"name": "TypeError", "message": "invalid arg", "stack": ...}}

Set Options via Code

const logger = require('simple-json-logger')

logger.options.printLevel = 40

logger.info('ok') // won't be printed

logger.warn('warning!') // printed

Set Options via Env

Set env variables:

export LOG_PRINT_LEVEL=40
export LOG_PRINT_PRETTY=true

Using default logger:

const logger = require('simple-json-logger')

logger.info('ok') // won't be printed

logger.warn('warning!') // printed with pretty

Clone

const logger = require('simple-json-logger')

logger.options.printPretty = true

const logger2 = logger.clone()

logger2.options.logTimestamp = true

logger.info('hi') // pretty without timestamp

logger2.info('hello') // pretty with timestamp

API

Options

(LOG_PRINT_LEVEL) printLevel = 30 - Only logs with level equal or greater than this will be printed
(LOG_PRINT_PRETTY) printPretty = false - Print logs with pretty format
(LOG_TIMESTAMP) logTimestamp = false - Add 'timestamp' to every logs
(LOG_TRACE) logTrace = false - Add 'trace' to every logs. Only for development
(LOG_POSITION) logPosition = false - Add 'position' to every logs. Only for development
meta = null - Object that will be merged into every logs. User should be careful to not to override the builtin fields
jsonStringifier - Help stringify the output object. See default-json-stringifier.js