js-logger

Simple logger utility that adds some color to the console, formatting, and error logging. The same common functions were being used on small utility scripts. Eventually they were separated for reusability accross projects.

npm install @codejamboree/js-logger

import logger from '@codejamboree/js-logger';
logger.debug('hello'); // log magenta
logger.log('hello'); // log standard white
logger.info('hello'); // log blue
logger.warn('hello'); // log yellow
logger.error('hello'); // log red

Colors

Color can also be extended with the ANSI helper.

logger.log(`This is ${logger.ansi.red('Red')}.`); // Colors as red.
logger.log(logger.ansi.bgRed('Red')); // background color is red

Colors available are black, red, green, yellow, blue, magenta, cyan, and white.

Timers

Timer labels are cyan.

logger.time('my label');
logger.timeLog('my label'); // time label colored in cyan
logger.timeEnd('my label'); // time label colored in cyan

Formatting

A few helper functions provide some common formatting.

• done displays the console log, and the word, "done"
• title displays a title centered
• section displays a sub-title centered. Can customize start/end tags

Text is centered at 40 characters wide, with wrapping.

logger.title('my title');
// ----------------------------------------
//                 my title
// ----------------------------------------
logger.title('my title '.repeat(6));
// ----------------------------------------
//  my title my title my title my title my 
//              title my title             
// ----------------------------------------
logger.section('my section');
// 
//           ---{ my section }---          
// 
logger.section('my section '.repeat(4));
//
//    ---{ my section my section my }---   
//       ---{ section my section }---      
//
logger.section('my section', '<<< ', ' >>>');
//
//            <<< my section >>>           
//
logger.done();
// Running time: 18.331ms
// done

Error Logging

The logger has a logError method which can accept errors, objects, arrays, strings, promises, buffers, and more. An attempt has been made to handle just about any type of data and log it appropriately.

logger.logError(new Error('The Error'));
// The Error
logger.logError('The string error');
// The string error
logger.logError(['Error 1', 'Error 2']);
// Error (Array)
//   Error 1
//   Error 2
logger.logError({error: 'The error key'});
// The error key
// NOTE: same for keys: errors, message, message, reason, reasons
logger.logError(Buffer.from('The buffer error'));
// The buffer error
logger.logError(Promise.resolve('The resolved value'));
// Error (Promise)
// The resolved value
logger.logError(Promise.reject('The rejected value'));
// Error (Promise)
// The rejected value
logger.logError(1); 
// Error: 1
logger.logError(false); 
// Error: false
logger.logError(new Date()); 
// Error (Date): 2024-08-31T05:50:06.145Z
logger.logError({unrecognized: 'The unknown value'});
// Error (Object)
//   { unrecognized: 'The unknown value' }
logger.logError(null);
// Error (Empty)
logger.logError(undefined);
// Error (Empty)
logger.logError("");
// Error (Empty)

If an error has some specific keys, they will be listed as well. Specifically, these are data and rawPacket.

logger.logError({
  error: 'The Error',
  data: 'the data',
  rawPacket: Buffer.from("Hello")
});
// The Error
//   Hello
//   the data

Console

The logger is separat from the console, but has many of the same method names. You can override the consoles methods (debug, info, timeStamp, timeEnd) to apply color.

console.debug('foo'); // writes foo in white
logger.attach();
console.debug('foo'); // writes "foo" in magenta
logger.restore();
console.debug('foo'); // writes foo in white

Ideal Script

import logger from '@codejamboree/js-logger';

const main = async () => {
  console.log('do something.');
}

try {
  logger.attach();
  logger.title('Script Name');
  main()
    .catch(logger.logError)
    .finally(logger.done);
} catch (e) {
  logger.logError(e);
  logger.done();
}