colorized-logger

Simple instantiable logger that prepends a customizable colorized message to every log message per logger instance.

1. Installation

~$ npm install --save colorized-logger

2. Usage

// Step 1: import ColorizedLogger

const { ColorizedLogger } = require("colorized-logger");

// Step 2: instantiate a new ColorizedLogger

const debugLogger = new ColorizedLogger("[debug]", ["green", "bold", "underline", "bgBlack"], function(message) {
 return message.startsWith("[debug]");
});

// Step 3: use your new ColorizedLogger instance

if(debugLogger.log("Something")) {
 debugLogger.log("Always will return true because of the callback: the message will always start with '[debug]'.");
} else {
 debugLogger.log("Never executed");
}

3. API

ColorizedLogger = require("colorized-logger").ColorizedLogger

Type: {Class}

Description: Class used to instantiate easily and fast new loggers with colorized prepended message, and configurable returned callbacks.

new ColorizedLogger(message:String, styles:Array, callback:Function)

Type: {Constructor}

Parameter: {String} message. Message to be prepended in every ColorizedLogger#log(...) call.

Parameter: {Array<String>} styles. Styles (colors, background colors and modifiers) applied to the prepended message of this logger. The colorization is based on chalk library. Possibilities are listed here:

Modifiers

· reset

· bold

· dim

· italic (Not widely supported)

· underline

· inverse

· hidden

· strikethrough (Not widely supported)

· visible (Text is emitted only if enabled)

Colors

· black

· red

· green

· yellow

· blue (On Windows the bright version is used since normal blue is illegible)

· magenta

· cyan

· white

· gray ("bright black")

· redBright

· greenBright

· yellowBright

· blueBright

· magentaBright

· cyanBright

· whiteBright

Background colors

· bgBlack

· bgRed

· bgGreen

· bgYellow

· bgBlue

· bgMagenta

· bgCyan

· bgWhite

· bgBlackBright

· bgRedBright

· bgGreenBright

· bgYellowBright

· bgBlueBright

· bgMagentaBright

· bgCyanBright

· bgWhiteBright

Parameter: {Function} callback. Function to which the message is passed in plain format (once it is printed by console). This function is the last call of the ColorizedLogger#log(...) call as a return statement. This means that what is returned by this callback, is returned by the ColorizedLogger#log(...) call. By default: () => {}.

Description: Creates a new {ColorizedLogger} instance.

ColorizedLogger#message

Type: {String}

Description: Message to be prepended on every ColorizedLogger#log(...) message logged. It is defined in the constructor call (parameter 1).

ColorizedLogger#styles

Type: {Array<String>}

Description: Styles to be used on the prepended message by the ColorizedLogger#log(...) call. It is defined in the constructor call (parameter 2).

ColorizedLogger#callback(message:String, parameters:Array)

Type: {Function}

Parameter: {String} message. Plain text of the log.

Parameter: {Array<Any>} parameters. Data passed to the ColorizedLogger#log(...) call, without modifications.

Returns: {Any}

Description: Callback called as return statement by the ColorizedLogger#log(...) call. It is defined in the constructor call (parameter 3). The parameters will be injected when the ColorizedLogger#log(...) is called.

ColorizedLogger#log(...args:Any)

Type: {Method}

Parameter: {Any} ...args. Pass any type of data. Each item passed will be stringified (unless it is already a {String}) and concatenated in the same log message. Functions are also accepted, and their inner code will be printed.

Returns: `{Any}

Description: Prints the message defined by ColorizeLogger#message with the styles specified at ColorizeLogger#styles and the items stringified afterwords. Finally, it returns what ColorizeLogger#callback(fullLoggedMessageAsPlainText, passedArguments) call returns when it is called like this.

ColorizedLogger.create(message:String, styles:Array, callback:Function)

Type: {Static method}

Returns: {ColorizedLogger}

Description: It does the same as the ColorizedLogger constructor, but statically.

ColorizedLogger.stringify(data:Any, beautify:Boolean)

Type: {Static method}

Parameter: {String} data. The data to be stringified.

Parameter: {String} beautify. Whether to beautify the message, or not. By default: true.

Returns: {String}

Description: It returns any type of data, but stringified as JSON ({Function}s are allowed too).

4. Test, coverage and documentation

To generate the coverage:

~$ npm run coverage

To do the tests:

~$ npm run test

To generate the documentation:

~$ npm run docs

5. Conclusion

This is a small and minimalistic tool to have a visual logger implemented in your projects. Fully customizable, the functional approach lets you implement your own transporters, beside the colorized logging, which is quite comfortable, to be honest, compared with other logging frameworks. In fact, despite being so minimalistic, this is my favorite logging framework for Node.js.

Fully tested and covered, you can rely on this logging framework for your projects.