ts-tiny-log

Installation

npm i ts-tiny-log

import { log } from 'ts-tiny-log/default';

log.info('Test!');

Basic Usage

There are 5 log-levels, fatal, error, warn, info, and debug. Each one accepts any number of arguments, and also accepts any type of variable, object, array, error, etc.

import { log } from 'ts-tiny-log/default';

// info level with a string variable
log.info('Hello, ', env.APP_TITLE);

// debug level with an object variable
log.debug({ foo: 'bar' });

try {
	something();
}
catch (e) {
	// error level with an Error variable
	log.error('Something broke!', e);
}

Settings

Configure the log by creating a new instance. Export this so you can import your custom logger in your application.

src/log.ts

import { Log } from 'ts-tiny-log';

export const log: Log = new Log({
	shouldWriteTimestamp: false
});

level

Set the level that will be logged. Any level below this will also be logged. For example, setting the level to warn means that only fatal, error, and warn entries will be displayed. info and debug will be ignored.

Default Value: LogLevel.info

Example:

import { Log } from 'ts-tiny-log';
import { LogLevel } from 'ts-tiny-log/levels';

export const log: Log = new Log({
	// Set the level to warn
	level: LogLevel.warn
});

log.fatal('will be displayed');
log.error('will be displayed');
log.warn('will be displayed');
log.info('will be ignored');
log.debug('will be ignored');

Output:

2022-01-17T12:59:24.115Z | fatal | will be displayed
2022-01-17T12:59:24.118Z | error | will be displayed
2022-01-17T12:59:24.118Z | warn  | will be displayed

shouldWriteTimestamp

Turn on/off timestamp column per log entry

Default Value: true

Example:

src/log.ts

import { Log } from '../src';

export const log: Log = new Log({
	// Don't write timestamps
	shouldWriteTimestamp: false
});

log.info('without timestamps');

Output:

info  | without timestamps

shouldWriteLogLevel

Description: Turn on/off log-level column per log entry

Default Value: true

Example:

import { Log } from '../src';

export const log: Log = new Log({
	// Don't write log-level
	shouldWriteLogLevel: false
});

log.info('without log-level');

Output:

2022-01-17T13:16:50.157Z | without log-level

shouldWriteThreadId & threadId

Description: Enable a threadId column for each log entry. Use the optional threadId option if you would like to specify a custom thread id, otherwise the threadId from node worker_threads is used.

Default Value: false

Example:

import { Log } from '../src';

export const log: Log = new Log({
	// Add thread id
	shouldWriteThreadId: true,
});

log.info('with thread id');

Output:

2022-01-17T13:16:50.157Z | info  | main	| with thread id

metadataFormat

Determines how metadata columns (such as log-level and timestamp) are displayed.

Default Value: Piped columns:

(str) => `${str} |`

Example:

import { Log } from '../src';

export const log: Log = new Log({
	// Use square brackets for columns
	metadataFormat: str => `[${str.trim().toUpperCase()}]`
});

log.info('uppercase with square brackets');

Output:

[2022-01-17T13:21:15.224Z] [INFO] uppercase with square brackets

standardOut & standardError

Stream log output to a custom function.

Default value: stdout (standardOut) and stderr (standardError)

Example In this example, output will be streamed to a file via a custom streamToFile() function:

import { Log } from '../src';
import { appendFileSync } from 'fs';

/**
 * Our custom streamToFile function
 * 
 * @param ...data Array of data. Each element in the array is a column of the line.
 */
function streamToFile(...data: any[]): void {
	appendFileSync('test.log', data.join(' ') + '\n');
}

// Set our custom Log
export const log: Log = new Log({
	standardOut: streamToFile,
	standardError: streamToFile,
});

log.info('with custom output stream');

test.log:

2022-01-17T15:34:26.807Z | info  | with custom output stream