@evokegroup/logger NPM

@evokegroup/logger

Console logging based on severity.

Class: Logger

constructor(severity, { output, retain, onLog })

Parameter	Type	Default	Description
severity	`Logger.Severity, number, string`	`Logger.Severity.Disabled`	The maximum severity to output
output	`boolean`	`true`	Output the messages to the console
retain	`Logger.Severity, number, string`	`Logger.Severity.Disabled`	Message severity level to retain for later retrieval via `getLogs()`
onLog	`function`		A function to call whenever a message is logged regardless of severity

Example

const Logger = require('@evokegroup/logger');
function doSomethingWithLogs(log) {
  // All logged messages are passed to this function as they are logged.
  // example: log = {
  //   severity: 2,
  //   logged: true,
  //   date: '2021-02-07T16:43:32.233Z',
  //   messages: [
  //     'Doing something'
  //   ]
  // }
}
const logger = new Logger(Logger.Severity.Info, { output: true, retain: Logger.Severity.Error, onLog: doSomethingWithLogs});
logger.info('Doing something'); // logged to console
logger.debug('Data', { firstName: 'John', lastName: 'Doe' }); // not logged to console
logger.error('An error occurred', new Error('Bad data')); // logged to console
// do other stuff
doSomthingWithTheLog(logger.getLogs()); // Only errors are retained and returned

Properties

Property	Type	Access	Description
severity	`Logger.Severity`	get	The `Logger.Severity` level

Methods

getLogs(severity)

Get the logged messages

Parameter	Type	Default	Description
severity	`Logger.Severity`	The retain severity	The minimum severity level. If not given falls back on the retain severity level passed when the Logger was instantiated

Example

const Logger = require('@evokegroup/logger');
const logger = new Logger(Logger.Severity.Error, { retain: Logger.Severity.Debug });
logger.info('Doing something'); // not logged to console
logger.debug('Data', { firstName: 'John', lastName: 'Doe' }); // not logged to console
logger.error('An error occurred', new Error('Bad data')); // logged

const allRetainedLogs = logger.getLogs();
/*
  [{
    severity: 2, logged: false, date: '2021-02-07T16:43:32.233Z', messages: ['Doing something']
  }, {
    severity: 3, logged: false, date: '2021-02-07T16:43:32.233Z', messages: ['Data', { firstName: 'John', lastName: 'Doe' }]
  }, {
    severity: 0, logged: true, date: '2021-02-07T16:43:32.233Z', messages: ['An error occurred', Error: Bad data)]
  }]
*/

const noDebug = logger.getLogs(Logger.Severity.Info);
/*
  noDebug = [{
    severity: 2, logged: false, date: '2021-02-07T16:43:32.233Z', messages: ['Doing something']
  }, {
    severity: 0, logged: true, date: '2021-02-07T16:43:32.233Z', messages: ['An error occurred', Error: Bad data)]
  }]
*/

debug(message, ...message)

Log messages with a Logger.Severity.Debug severity level and using console.debug.

Parameter	Type	Default	Description
messages	`*`		The messages to log

Example

const Logger = require('@evokegroup/logger');

const logger_1 = new Logger(Logger.Severity.Debug);
logger_1.debug('Details', { firstName: 'John', lastName: 'Doe' });
// Expected output:
// Details
// { firstName: 'John', lastName: 'Doe' }

const logger_2 = new Logger(Logger.Severity.Error);
logger_2.debug('Details', { firstName: 'John', lastName: 'Doe' }); // This message will not be logged since the logger's maximum severity level is less than Logger.Severity.Debug

error(message, ...message)

Log messages with a Logger.Severity.Error severity level and using console.error.

Parameter	Type	Default	Description
messages	`*`		The messages to log

info(message, ...message)

Log messages with a Logger.Severity.Info severity level and using console.info.

Parameter	Type	Default	Description
messages	`*`		The messages to log

log(severity, message, ...message)

Log messages

Parameter	Type	Default	Description
severity	`Logger.Severity, number, string`	`Logger.Severity.Disabled`	The message severity level
messages	`*`		The messages to log

Example

const Logger = require('@evokegroup/logger');

const logger = new Logger(Logger.Severity.Error);
logger.log(Logger.Severity.Error, 'Error');
// Expected output:
// Error