Js-standard-logger NPM

js-standard-logger

A useful standard Logger for JS, based on winston, formatting simple output for log, saving to demanded path. Common output as: [2018-12-11 09:41:19] [info] [sample-label] --- it s info

1. Install

$ npm install --save js-standard-logger

2. Usage

const Logger = require('js-standard-logger')
const logger = new Logger('/data/logs/logger-sample/') // simply initialize


logger.exec('it s info') // default for info level output
//[2018-12-11 09:41:19] [info] [sample-label] --- it s info

logger.exec(`${Logger.stringify({it:'can be object',also:['can','be','array']}, true)}`,Logger.WARN()) // choose diff level
//[2019-03-27 14:20:55] [warn] [test] --- {
//  "it": "can be object",
//  "also": [
//    "can",
//     ...
//  ]
//}

logger.exceptionThrows('log and throw err') // do log and throw err, which required try-catch
//[2018-12-11 09:41:19] [error] [sample-label] --- log and throw err

logger.exec('it s error', Logger.ERROR(), new TypeError('get type error')) // log err stack
//[2019-01-29 09:29:43] [error] [test] --- it s error . err stack : TypeError: get type error
//    at Object.<anonymous> (/home/roren/Documents/source/self/logger/test.js:9:45)
//    at Module._compile (internal/modules/cjs/loader.js:686:14)
//    ...

3. Api

Init

Please fill with absolute path.

const Logger = require('js-standard-logger')
const logger = new Logger('/data/logs/log-save-dir/', 'log-name.log','default-label', Logger.INFO())

arguments	required	description
log_save_dir	true	dir abstract path to save log (auto mkdir if not exists)
log_name	false	default to "app.log"
label	false	label to differ log, default to log_name
view_level	false	choose viewing output level, using Logger fields, default to debug

Function

logger.exec()

Do log on message with different level

arguments	required	description
message	true	message to log
level	false	tag the label according to level field, default to info
err	false	Error instance, will logged stack

logger.exceptionThrows()

Do log on message and throw error, which recommended to catch outside

arguments	required	description
message	true	message to log
level	false	tag the label according to level field, default to error

Logger.inspect()

inspect object to view

arguments	required	description
object	true	inspect object

Logger.stringify()

Transform object to string when logging

arguments	required	description
object	true	stringify object type to do log
pretty	false	pretty json output, default false

Field

Different level fields to choose

Fields	Level	Description
Logger.DEBUG()	debug	tags for development debug
Logger.INFO()	information	tags for information
Logger.WARN()	warning	tags for that be bad for some features
Logger.ERROR()	error	tags for that intercept process or functional crash