Sfs-logger NPM

SFS-Logger

Before all, this is my first package so I hope it's not too shitty !

This is a lightweigh Logger tool I made to avoid usage of bundled loggers with dependencies.

Getting Started

Prerequisites

To install this package, you need only one thing : NodeJS > 10.15.

You can use it for both Javascript and Typescript.

Installing

To install, just run this command :

npm install --save sfs-logger@latest

How to use

Basic example

Typescript

First you need an instance of Logger class :

import { ILogger, Logger } from "sfs-logger";

const logger: ILogger = new Logger("./logs", "development");

/* First parameter is the path to the directory where you want to store your log files.
   Second parameter is the name of the environment application is running on. */

Then you can just use it like following :

import { ILogger, Logger } from "sfs-logger";

const logger: ILogger = new Logger("./logs", "development");

logger.debug("Let's try it !");
logger.error("Wow, incredible !");
logger.info("As sample as it needs to be.");
logger.warn("An other one !");

Javascript

First you need an instance of Logger class :

const sfsLogger = require("sfs-logger");

const logger = new sfsLogger.Logger("./logs", "development");

/* First parameter is the path to the directory where you want to store your log files.
   Second parameter is the name of the environment application is running on. */

Then you can just use it like following :

const sfsLogger = require("sfs-logger");

const logger = new sfsLogger.Logger("./logs", "development");

logger.debug("Let's try it !");
logger.error("Wow, incredible !");
logger.info("As sample as it needs to be.");
logger.warn("An other one !");

Advanced usage

If you want to use this logger as your main logger, there are several things to know.

Printing object

You can obviously print object instead of strings if you need to track objects status or for debugging purpose.

For example :

const sfsLogger = require("sfs-logger");

const logger = new sfsLogger.Logger("./logs", "development");
const objectToPrint = { foo: "bar" };

logger.debug(objectToPrint);

Above code will result by an entry similar to this one :

2019-01-01T10:00:00.000Z [DEBUG] {
 "foo": "bar"
}

Debug level

Debug level is working only in development and test modes. So if you forget to remove .debug() calls, these messages won't appear in log files.

How to inject

If you use Dependency Injection through your project, you can inject Logger in classes where you need it. I wouldn't recommand it anyway because a logger should not appear in class constructor.

I would rather recommand to instanciate it in a file and to export the created instance like below :

/* myLogger.ts */
import { ILogger, Logger } from "sfs-logger";

const logger: ILogger = new Logger("./logs", "development");

export { logger };

And then to import it wherever it's needed :

/* An other file.ts */
import { logger } from "./**/myFile";

export class FooBar {
    foo() {
        logger.info("foo() is called");
        return "foo";
    }

    bar() {
        logger.info("bar() is called");
        return "bar";
    }
}

Javascript usage

It's quite similar to Typescript / ES6 usage :

/* myLogger.js */
const sfsLogger = require("sfs-logger");

const logger = new sfsLogger.Logger("./logs", "development");

module.exports = logger;

/* An other file.js */
const logger = require("./path/to/myLogger");

module.exports = class FooBar {
    foo() {
        logger.info("foo() is called");
        return "foo";
    }

    bar() {
        logger.info("bar() is called");
        return "bar";
    }
}