Satisfact-api / Logger

Simple and easy to use text logger.

Usage

The logger must be initialized then can be called with one of the four log levels:

• trace
• info
• warn
• error

import Logger from 'project-logger';

const logger = Logger('context');

logger.warn('Here comes an object');
logger.warn({
  hello: 'World',
});

Output:

Reference

The Logger module exports a factory function that is used to generate loggers instances.

• Factory
• configure
• Instance

Factory

Logger([context], [options])

Logger([options])

The factory generates logger instances, it can be initialized with a context and with options.

If no context is provided, the logger will take the current file location as context.

Examples:

import Logger from 'logger';

// Simple initialization with a context
const simple = Logger('my-context');

// No context provided, the file location will be used
const noContext = Logger();

// The logger instance can be initialized with some options
const withOptions = Logger('my-context', {
  trim: false,
});

Options

The options attribute is an object that can contains :

• colors (object): Object defining the colors used for each kind of log levels: trace, info, warn, error. Each attribute of the color option must be a function that will receive an input and returns it colorized. Internally, chalk do the default colorization. If null, colorization is disabled.
• dateFormat (string): Date format used to display the dates. The formater being [dayjs][days], the format must follow their own format described here. If null or empty, no date will be displayed.
• trim (boolean): Option to toggle the trim of each strings to log. It does not affect objects and errors.
• ignoreEmpty (boolean): Option to toggle the empty lines removal.
• output (function): Output method called for each line to display. Defaults to process.stdout.write.
• logLevel (string): Minimum log level to diplay. Can be either TRACE, INFO, WARN or ERROR. Defaults to process.env.LOG_LEVEL or WARN if it does not exists.

configure

configure(options)

The module also export a method overriding the global configuration of all the Logger instances. It takes the same arguments as the Factory options.

Instance

Each instance consist of 4 methods: trace, info, warn, error:

logger.trace(content)

logger.info(content)

logger.warn(content)

logger.error(content)

The attribute content can be a string, object or error. The log only outputs if the configured log level is equal or "inferior" of the log method.

Get the current log level

getLogLevel()

You can retrieve the current log level with the method getLogLevel. It can be useful if you need to conditionnaly start heavy log loops on your processes.