@emooa/logger

Logger

@emooa/logger is a simple logger for use with Nodejs, developed through TS and designed as a simple logging library that supports multiple transports.

Installation

npm install @emooa/logger
// or
yarn add @emooa/logger

Usage

@emooa/logger supports both import import and require import modes.

CommonJS

const Logger = require("@emooa/logger");

ESM

import Logger from "@emooa/logger";

Simple example:

const Logger = require("@emooa/logger");

const logger = new Logger({
  category: "My Project",
});

logger.log("The color is grey!");
logger.info("The color is green!");
logger.warn("The color is yellow!");
logger.error("The color is red!");
logger.debug("The color is cyan!");

This will then output to stdout with the coloured layout

[2023-12-17 12:56:25] [LOG] My Project - The color is grey!
[2023-12-17 12:56:25] [INFO] My Project - The color is green!
[2023-12-17 12:56:25] [WARN] My Project - The color is yellow!
[2023-12-17 12:56:25] [ERROR] My Project - The color is red!
[2023-12-17 12:56:25] [DEBUG] My Project - The color is cyan!

Appender example:

• Currently, 4 appender types are supported, namely stdout, console, stderr, and file.

• When the appender type is a File, the file custom configuration log format is supported.

• 3 layout types are supported, namely message, basic and pattern. The default is basic, and the output format is %[[%d] [%p]%] %m.

• When the layout type is pattern, it allows you to define any format you want.

const Logger = require("@emooa/logger");

const logger = new Logger({
  category: "My Project",
  appenders: [
    {
      type: "stdout", // "console" | "stderr" | "stdout" | "file"
      colour: true,
      layout: {
        type: "pattern", // message, basic, pattern,
        pattern: "%[[%d] [%p]%] %m",
      },
    },
    {
      type: "file",
      colour: false,
      file: {
        filename: "log/emooa-logger.log",
        options: {
          keepFileExt: true,
        },
      },
      layout: {
        type: "basic",
      },
    },
  ],
});

logger.log("The color is grey!");
logger.info("The color is green!");
logger.warn("The color is yellow!");
logger.error("The color is red!");
logger.debug("The color is cyan!");

More examples: Examples.

API

Appender

Parameters	Type	Default value	Definition
type	console｜stderr｜stdout｜file (Required)	null	coloured console logging to stdout or stderr.
colour	boolean (Optional)	true	Whether to output colored logs.
layout	Layout (Required)	{ type: 'basic' }	The appemder layout, supports multiple log output formats.
file	File (Required when the type is file)	{ filename: 'logs/emooa-logger.log' }	file appender, with configurable log rolling based on file size or date.

Layout

The appender layout, supports multiple log output formats

Parameters	Type	Default value	Definition
type	basic｜message｜ pattern (Required)	basic	basic[time] [logLevel] category - message message simple message pattern A special type that allows you to define any format you want.
pattern	string (Required when the output style is pattern)	%[[%d] [%p]%] %m	A special type that allows you to define any format you want.

File

file appender, with configurable log rolling based on file size or date, Read More.

• filename - defaults to logs/emooa-logger.log.
• maxSize - defaults to 0 - the size in bytes to trigger a rollover. If not specified or 0, then no log rolling will happen.
• numBackups - defaults to 1 - the number of old files to keep (excluding the hot file).
• options
  • encoding - defaults to 'utf8'.
  • mode - defaults to 0o600 (see node.js file modes).
  • flags - defaults to 'a' (see node.js file flags).
  • compress - defaults to false - compress the backup files using gzip (backup files will have .gz extension).
  • keepFileExt - defaults to false - preserve the file extension when rotating log files (file.log becomes file.1.log instead of file.log.1).
  • fileNameSep - defaults to '.' - the filename separator when rolling. e.g.: abc.log.1 or abc.1.log (keepFileExt).

License

MIT Licensed
Copyright (c) 2023 Emooa