@studimax/logger

A logger system with configurable transporters.

Installation

npm install @studimax/logger
# or
yarn add @studimax/logger

Description

The logger system is a simple and flexible logging system. It is designed to be used in a modular way, so that you can easily add new transports.

2021-12-22 13:23:58.47	<error>	Logger.spec.ts:5	(Object.<anonymous>)    log1 {"hello":"world"}

Usage

import Logger from '@studimax/logger';

const logger = Logger({
    transports: [Logger.TRANSPORTS.CONSOLE_LOG(), Logger.TRANSPORTS.DATED_LOG()],
    levels: {
        extra: {
            color: '#ff0000',
            level: 1,
        },
    },
});
logger.info('Hello World!');
logger.extra('Extra!');

Logger default options

import Logger from '@studimax/logger';
Logger({
    format: '{timestamp}\t<{level.name}>\t{file}:{line}\t({method})\t{message} {metadata}', //see format docs
    dateFormat: 'YYYY-MM-DD HH:mm:ss.SS', // use fecha to format date
    logFolder: 'logs',
    logHistory: 100, // keep 100 logs
    transports: [], // by default, no transports
    transportTimeout: 1000, // timeout for transports
    levels: {}, // by default, use default levels but can be overridden
})

Default Levels

The color is used to display the level name in the console.

Description	Level	Tag	Color
Trace	0	trace	#0099ff
Debug	1	debug	#00cc99
Info	2	info	#00cc30
Warn	3	warn	#ffcc00
Error	4	error	#ff0000
Fatal	5	fatal	#a70000

Custom Levels

const levels = {
    myCustomTag: {
        color: '#ff0000',
        level: 1
    }
}

Custom Format

Format is a string that can contain the following placeholders:

• {timestamp}: the timestamp of the log formatted with the dateFormat option
• {level}: level object containing name, level and color
• {file}: the file where the log was called
• {line}: the line where the log was called
• {method}: the method where the log was called
• {message}: the message of the log
• {metadata}: the metadata object passed to the log

You can use the dot notation . to access nested properties. For example, {metadata.foo} will access the foo property of the metadata object. See @studimax/ts package for more information.

Transporters

This package provides the following transporters:

CONSOLE_LOG

This transporter logs to the console.

DATED_LOG

This transporter logs to a file with a date prefix. The file is created if it doesn't exist. This transporter implements the FIFO strategy, first log is the first to be written.

NAMED_LOG

This transporter logs to a file with a name prefix.

Custom Transporter

You can create your own transporters by creating an async function.

async function MyCustomTransporter(data: Data, options: TransportOptions) {
    if(await options.transportReady){
        // do something when the same previous logs transport has been resolved.
        console.log(data.message);
    }
}

TransportOptions extends LoggerOptions ans add more properties:

• ready: a promise that is resolved when all previous logs transports have been resolved.
• transportReady: a promise that is resolved when the same previous logs transport has been resolved.