tilo

© 2021, Onur Yıldırım (@onury). MIT License.

Tiny logger with styles and levels for Node/TypeScript.

npm i tilo

Usage

// Node/CommonJS environments
const { Tilo } = require('tilo');

// With modern ES / transpilers
import { Tilo } from 'tilo';

// Usage:
const tilo = new Tilo({ level: 'debug' });
tilo.info('Output colorful logs with date/time and level info.');

Read the concise API reference.

Formatted Output

You can provide a custom function that returns a formatted string.

tilo.format = (info, chalk) => {
    const text = `${info.time} ${info.level.toUpperCase()}\t${info.text}`;
    return info.level === Tilo.Level.ERROR
        ? chalk.red(text)
        : chalk.white(text);
};
tilo.info('Custom formatted log...');
// —> 15:30:43 INFO   Custom formatted log...

Safely Stringified Logs

You can log safely strigified objects (i.e. with circular references).
Use #s() to stringify an individual or multiple values.
#sp() is for stringify with pretty format & indents.

tilo.info(tilo.s({ key: 'stringify' }));
tilo.warn(tilo.sp({ key: 'stringify pretty' }));

Configuration

Pass an options object to constructor, with the following properties:

Option	Type	Default	Description
enabled	boolean	true	Whether log output is enabled.
level	string	"debug"	Logging level. You can use Tilo.Level enumeration.
format	LogFormatFn	Tilo.defaultFormat	Function for formatting and styling. Set to null to disable formatting.
styles	boolean	true	Specifies whether styles and colors are enabled.
streams	ILogLevelStreams | NodeJS.WriteStream	process.stdout	A hash-map of objects that defines write streams for each individual log level. If set to a single stream, it's treated as default for each log level.
cleanStack	boolean | string[]	false	If set to true, stack lines with no file-path in them will be removed. Or set to a list of case-sensitive keywords to be filtered out from the stacks.

Log Levels and Methods

Level / Priority		Methods	Details
ERROR	0	#error()	Error logs. Always printed to the stream.
WARN	1	#warn()	Warning logs.
INFO	2	#info()	Informational logs. Alias: #ok()
		#plain()	Regardless the configuration, output has no formatting. Clean text.
		#table()	Prints a visual table to the stream with the given data.
VERBOSE	3	#verbose()	Verbose logs.
DEBUG	4	#debug()	Debug logs.
		#dir()	Inspects the given object and prints the result to the stream.
		#trace()	Prints the message to the stream with stack trace to the current position in code.
SILLY	5	#silly()	Silly logs.

There is also a #log() method which is INFO level by default. But you can pass the log level as the first argument to change that:

tilo.log('debug', 'message...');

Log Event

Tilo is also an EventEmitter. You can run custom functionallity on the log event.

tilo.on('log', logInfo => {
    if (logInfo.level === 'error' && /\bfatal/i.test(logInfo.text)) {
        // e.g. send email to admin
    }
});

Changelog

v2.0.1 (2023-03-20)

• Handle edge-case inputs.

v2.0.0 (2020-01-31)

• Drop support for Node v6.
• Update dependencies to latest version.

v1.0.0 (2019-01-28)

• initial release.

License

MIT.