API

Note: This module is written in ES2015 JavaScript so make sure you have a basic understanding for ES2015 before you continue reading.

Using the logger

Print logs to stdout

You can pipe any writeable stream to a Logger by calling Logger#pipe. As stout is such a writable stream it can be piped directly:

import Logger from '@ls-age';

Logger.pipe(process.stdout);

By default, this tells the logger to print all error, warn and info messages to stdout. You can also pass a logLevel option to print just specific messages:

Logger.pipe({ logLevel: Logger.LEVEL_ERROR });

Log types and levels

By default, the error, warn, info and debug are used as types.

A logger has different message types. Each type has it's own logging function and level. E.g. when a Logger instance has a info log type, it creates the logging function Logger#info and the level constant Logger#LEVEL_INFO.

In our example we can log messages by calling:

import Logger from '@ls-age';

Logger.info('Debug message');

Using different log types makes it possible to adjust the logger's output. When a stream (e.g. stdout) is piped to the logger, only messages with the specified log level or higher are written. For the default log types this means:

Create a custom instance

By default, a single shared instance of the Logger class is exported. You can create also create custom instance:

import { Logger } from '@ls-age/logger';

const customLogger = new Logger();

References