Rear-logger NPM

rear-logger

A logger for Rear projects.

How it works

Create a logger with name and options, then start logging on the predefined levels: success, info, warn, debug and error.

Level names can be added or customized by providing a key/value map with level name and color string in the levels option. You can also specify both terminal and browser colors by providing an Array with both values as shown below.

const createLogger = require('rear-logger');

const name = 'MyAwesomeLogger';
const options = {
  showName: true,
  showDiffLabel: true,
  levels: {
    hint: ['cyan', 'color: cyan'] // or just 'cyan'
  }
};

const logger = createLogger(name, options);
logger.hint('Logger "%s" created with options: %O', name, options);

Default Levels

Name	Color
log	white
none	white
debug	magenta
info	blue
success	green
hint	yellow
warn	yellow
warning	yellow
error	red
quit	red
GET	bold_green
POST	bold_yellow
PUT	bold_blue
DELETE	bold_red
OPTIONS	bold_cyan

Logger Options

Name	Type	Default	Description
enabled	bool	true	Enable or disable the logger output
showName	bool	false	Prefix logger's name to the logged output
nameColor	Array		Define logger's name color
showLevelName	bool	true	Print the log level in logged output
showTimeLabel	bool	false	Print the current time in the logged output
showDiffLabel	bool	false	Print the diff time from last logged messaged
formatters	?object	{}	Accept additional text formatters
codeMap	object		Define additional code map (i.e. emoji-codes)
disableCodeMap	bool	false	Define code-map conversion (i.e. emoji-codes)
levels	?object	{}	Define key/value level name and color pairs
stdout	?function		Custom stdout
stderr	?function		Custom stderr

API

constructor (name: string, props: RearLoggerProps)

Create a new logger with given name and options.

Parameters

raw (message: string, ...args: Array): void

Print a message directly to the stdout much like a standard console.log would do.

Parameters

message (level: string, message: string, ...args: Array): void

Format and print a message for the given level. Note: usually is more convenient to call the logger's level function as in logger.info('Hello world')

Parameters

warn (assert?: boolean, message: string, ...args: Array): void

Format and print a warning message. When an assert is provided, the message is conditionally printed based on the truthyness of the assertion.

Parameters

error (message: string|Error, ...args: Array): void

Format and print an Error's message or a given message to the stderr.

Parameters

debug (message: string, ...args: Array): void

Format and print a debug message. The DEBUG environment variable is used to show or hide this message based on space or comma-delimited names.

The character may be used as a wildcard. For example: `DEBUG=myLogger:`

For example:

export DEBUG="firstLogger:*"

const firstLogger = require('logger')('firstLogger:section');
const secondLogger = require('logger')('secondLogger:section');

firstLogger.debug('This message will be printed to stdout');
secondLogger.debug('This message will NOT be printed to stdout');

Note: Set the DEBUG variable in the localStorage if you are using the library from a browser.