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 |