Rainlog NPM | npm.io

Rainlog Node.js Logger with Color support

This versatile logger is an advanced console.log for your applications. It uses the built in util.format to make it easy to output strings and objects (no more need for JSON.stringify), and also has the excellent chalk library built in.

You can also log to file by setting it up in the configuration.

INSTALL

npm i rainlog or yarn add rainlog

USAGE

By default 2 loggers are included: info and err. You can add extra loggers as you please.

const Rainlog = require('rainlog')
const log = new Rainlog()

// Write to console.log using the 'info' logger
log.info('hello world')

// Write to console.log using the 'error' logger
log.err('hello world')

// Update config for a single logger
log.get.err.set({ file: 'error.txt' })

// Update config for all loggers
log.set({ quiet: true })

// Reset config for a single logger
log.get.info.reset()

// Reset config for all loggers
log.reset()

// Write formatted text
log.info('%s %d %o', 'hello', 2020, { world: 'amazing' })
// Output: hello 2020 { world: 'amazing' }

// Use the $ function to write to file
log.$info('hello')

// Add a logger to the existing log, pass name and config
// The new logger is instantly available as 'log.warn'
log.add('warn', { quiet: true })
log.warn('this logger is on fire')

// Create multiple logs if you want
access = new Rainlog()
access.info('user accessed')
access.err('user not found')

FORMATTING

Here are the formatting options, taken from the Node.js docs:

%s - String.
%d - Number (integer or floating point value) or BigInt.
%i - Integer or BigInt.
%f - Floating point value.
%j - JSON. Replaced with the string '[Circular]' if the argument contains circular references.
%o - Object. A string representation of an object with generic JavaScript object formatting. Similar to util.inspect() with options { showHidden: true, showProxy: true }. This will show the full object including non-enumerable properties and proxies.
%O - Object. A string representation of an object with generic JavaScript object formatting. Similar to util.inspect() without options. This will show the full object not including non-enumerable properties and proxies.
%% - single percent sign ('%'). This does not consume an argument.

CONFIGURATION

Use the 'set' function to configure your logger. Files are not written to by default.

// The default configuration looks like this for all loggers
{
  // When quiet is true there will be no output to console
  quiet: process.env.NODE_ENV === 'production',

  // Set the file option to a file name to also write to file
  file: false,

  // Set colors and modifers, see the 'chalk' module for options
  style: 'green.bold.underline'
}

// Create the Rainlog instance
const log = new Rainlog()

// Optionally pass the config to the constructor
const log = new Rainlog({ quiet: true })

// Use the set function to configure your logger
log.get.info.set({ file: 'info.txt' })
log.get.err.set({ file: 'error.txt' })