OneLineLogger

Simple no-fuss colorised logging for NodeJS

Feature Overview

• Light-weight, quick to setup and easy to use.
• Multiple logger instances
• Customizable logger prefixes (to help distinguish logging from different modules)
• One line statement to optionally upgrade (colorize and timestamp) all existing uses of console.log(), console.info(), console.warn() and console.error() throughout a code base.
• Log to file.
• Configurable logging levels - DEBUG, INFO, WARN & ERROR.

Please note OneLineLogger is for NodeJS. It will not work in Web Browsers.

Installing

NPM

npm install onelinelogger

GIT

Clone from GIT and install dependencies.

git clone https://github.com/garyns/OneLineLogger.git
cd OneLineLogger
npm install

Examples

Basic Usage

// Variable logger is considered the 'default logger' instance. Custom loggers are discussed later.
var logger = require("onelinelogger");

logger.log("Call to logger.log()");
logger.info("Call to logger.info()");
logger.warn("Call to logger.warn()");
logger.error("Call to logger.error()");
logger.debug("Call to logger.debug()");
logger.highlight("Call to logger.highlight()");

Here is the output:

For onelinelogger 1.1.2+ logger.boo() is an alias for logger.highlight()

Overloading console.log() and related functions

var logger = require("onelinelogger");

// Before Overloading
console.log("Call to console.log()");
console.info("Call to console.info()");
console.warn("Call to console.warn()");
console.error("Call to console.error()");

// Overload with default logger
logger.replaceConsole();

console.log("Call to console.log()");
console.info("Call to console.info()");
console.warn("Call to console.warn()");
console.error("Call to console.error()");
console.debug("Call to console.debug()");
console.highlight("Call to console.highlight()");

Here is the output (spacing added):

Custom Logger Instance

Create custom loggers to help associate log entries with different parts of your code.

// Default Logger instance
var logger = require("onelinelogger");

// Custom Logger instance
// [MY_LOGGER] is now added to every line
var myLogger = logger.create("MY_LOGGER");

myLogger.log("Call to myLogger.log()");
myLogger.info("Call to myLogger.info()");
myLogger.warn("Call to myLogger.warn()");
myLogger.error("Call to myLogger.error()");
myLogger.debug("Call to myLogger.debug()");
myLogger.highlight("Call to myLogger.highlight()");


// Alternatively, you could...
var myLogger2 = require("onelinelogger").create("MY_LOGGER2");

Here is the output:

You can change the 'prefix' of a logger by calling setPrefix().

var logger = require("onelinelogger");

// Output of default logger now prefixed with [MAIN]
logger.setPrefix("MAIN");

// Customer Logger - [MY_LOGGER] is added to every line...
var myLogger = logger.create("MY_LOGGER");

// ... And now it's [THEIR_LOGGER]
myLogger.setPrefix("THEIR_LOGGER");

Global Settings

These settings affect ALL logger instances - that is the default logger and any custom loggers you create.

var logger = require("onelinelogger");

// Append all output to a file
logger.setGlobalFile("log.txt");

// Stop logging to a file
logger.setGlobalFile(null);

// Set the length of the prefix text
// Tweaking this property helps you keep your text lining up
// Eg 0 -> [MAIN], where 10 -> [MAIN     ]
logger.setGlobalPrefixLength(10);

// Set Logging Level to one of constants logger.DEBUG logger.INFO (default), logger.NOTICE, logger.WARN or logger.ERROR, or alternatively the strings DEBUG, INFO, NOTICE, WARN or ERROR
logger.setLevel(logger.INFO)
logger.setLevel("WARN")

// Get Logging Level (as Number 0 - 4).
const currentLogLevel = logger.getLevel()

// Get Logging Level Name (DEBUG, INFO, NOTICE, WARN or ERROR)
const currentLogLevelName = logger.getLevelName()


// Suppress (false) or show (true) calls to .debug()
// NOTE deprecated in v1.1.2. Use setLevel(logger.DEBUG) instead.
logger.setGlobalDebugging(true);

// Check if log level is logger.DEBUG
const debugging = logger.isDebug();

// The previous isDebug() example is equivalent to
const debugging = logger.getLevel() === logger.DEBUG