MK Simple Logger

This a small package for node that allow implement a logger, and add same config options, like theming or set custom format.

ℹ️ℹ️ Since versión 0.1.11 the output is formatted for logger's name and log's level

Install

The package is available in npm repositories. npm install

npm install mk-simple-logger

yarn install

yarn add mk-simple-logger

Usage

The main class is SimpleLogger so you need to import from the module

const SimpleLogger = require("mk-simple-logger").SimpleLogger;
// or
const { SimpleLogger } = require('mk-simple-logger');
let logger = new SimpleLogger("mylogger");
logger.info("My Message");
// -> 20/02/2021 @ 20:10:40 - [ info ] - mylogger - My message

// allow string foramtting
logger.critical("My {p} message", { p: "custom" });
// -> 20/02/2021 @ 20:10:40 - [ CRITICAL ] - mylogger - My custom message

Methods

logger.debug("");
logger.info("");
logger.log("");
logger.warn("");
logger.error("");
logger.critical("");

Set the log level

SimpleLogger.setLogLevel("debug"); // 'warn'| 'info' | 'log' | 'error' |
'critical'

Set custom format

The class allow change the date and the log line format:

SimpleLogger.setFormat("{name} ==> {msg}");
// on log: mylogger ==> My message
SimpleLogger.setDateFormat("{y}/{month}/{day}");
// on write date: 21/03/14

Available log fields:

{name}  - logger name
{level} - loging level
{date}  - log date
{msg}   - log message

Available date format:

{day}     - current day
{weekDay} - day of the week
{month}   - the month
{year}    - the full year
{y}       - the short year
{hour}    - the hour
{min}     - the minuts
{sec}     - the seconds
{mil}     - the miliseconds

Enable the file logger

SimpleLogger class can manger a file log too, this option need to set the static option isFile as true and set the logFile:

SimpleLogger.enableFileLog(); // enable file log
SimpleLogger.setFileLog("myapp.log"); //setting the file log
// if you want you can disable the stdout with:
SimpleLogger.disableStdout();

Logger can work with two options at the same time, they'r not restrictive.

Load configuration from the env

Simple logger can load same data from the enviroment if it's set. Can load:

• LEVEL as logLevel
• LOG_FILE for set the log's file
• ERROR_FILE for set the errors' file
• If NODE_ENV is set read it and set the log level from this env variable

Global usage

It's posible to use the logger globally, for this prupose from version 0.1.4 has the static method global() that return an static instance of the logger:

	const {SimpleLogger} = require('mk-simple-logger');
	SimpleLogger.global().log('message'); // can access to all log method
	SimpleLogger.global().setName('name'); // can set the girglobal logger name

All methods all available for the glogal logger.

Express integration

Sice version 0.1.8 can use built logger for express applications:

function logger(?name: string, ?level: string, ?format: string): ExpressMiddlewar

⚠️❗ Since 0.1.9 you can set a custom format

Usage in express

const express =  require('express');
const app = express();
const {SimpleLogger, logger} = require('mk-simple-logger');
app.use(express.json());
...
app.use(logger("SERVER", "info", "{method} {url} {status} {time}ms"));
...
app.listen(8080);

On request:

GET /uri1
logger:
18-02-22 @ 19:43:50 [ INFO ] -> SERVER -> GET /uri1 300 3ms

The logger work like the main logger so you can enable the file logger.

Format

Since 0.1.9

The format param let you customize the message body, in this case, like the logger format, we have a prefixed mapped data:

| FIELD | Description | |------|----------------| | {time} | Request time | | {method} | Request method | | {url} | Request url | | {status} | Response status code |

You can play with this paramaters to generate a custom log mesage format.