README

Sloggy

Node.js logging solution

Installation

npm i sloggy

Example Usage

const FileLogger = require("sloggy");

let logger = new FileLogger({dir: "log"});

logger.info("Something happened");

Or more complex example:

const { FileLogger, Message } = require("sloggy");

let logger = new FileLogger({dir: "log"});

logger.info("Something happened"); 

let message1 = new Message("Doing something");
let message2 = new Message("still doing something...");
let nestedMessage = Message.add(message1, [message2, "finished doing something..."]);
logger.info(nestedMessage);

logger.error("Error occured!");

The above example will log following lines to log/main.log inside your working directory:

I, [2018-11-12T01:56:00.462Z] INFO  -- : Doing something
I, [2018-11-12T01:56:00.462Z] INFO  -- :   still doing something...
I, [2018-11-12T01:56:00.462Z] INFO  -- :   finished doing something...
E, [2018-11-12T01:56:00.463Z] ERROR -- : Error occured!

Log Levels

{
  fatal: 0,
  error: 1,
  warn: 2,
  info: 3,
  debug: 4
};

There is also a special log level all that you can pass to FileLogger constructor to log every message regardless of its level.

Logger API

FileLogger constructor

new FileLogger(options);

options.dir: a string, path to directory. Required.
options.level: a string, maximum log level to log at. Everything above is ignored. Default: "info".
options.logFile: a string, filename for the main logfile. Default: "main.log".
options.errorLogfile: a string, filename for the separate error file. If set, all errors will also be logged to this file. Disabled by default.

FileLogger methods

Every method logs the message with corresponding log level(e.g. INFO) and returns a Promise which resolves either with logged message string or undefined if message was ignored due to options.level setting.

logger.fatal(message);
logger.error(message);
logger.warn(message);
logger.info(message);
logger.debug(message);

message: a string, a Message or an Error.

Message API

Message constructor

new Message(message);

message: a string or an Error.

Message.add

Creates an instance of Message with any number of sub-messages. Sub-messages will be logged along the parent message and marked with identation. Works with any level of nesting. Note that this method does not modify parent and returns a new message object.

Message.add(parent, child|children);

parent: an instance of Message class.
child: a string or a Message.
children: an array of strings or instances of Message class.

DumbLogger

Has exactly same API as FileLogger but does not log anything into files. Can be used interchangeably in cases when you don't need any logs(e.g development, testing)

const { DumbLogger } = require("sloggy");

let logger = new DumbLogger("dir", {logFile: "production.log"});

logger.info("Will not be logged").then(m => console.log(m));
//=> I, [2018-11-12T02:25:08.335Z]  INFO -- : Will not be logged

License

MIT

Usage no npm install needed!