loglevel-mixin

loglevel-mixin

Injects methods named after a set of logLevels which are only forwarding messages. If the current logLevel is higher or equal to the logLevel the name of the called method reflects.

So the model object itself can be used as a logger and the log level is directly attaches to the model

usage

import { defineLogLevelProperties, defineLoggerMethods } from 'loglevel-mixin';

let someObject = {
  log(severity, message) {
    console.log(`${severity} ${message}`);
  }
};

defineLoggerMethods(someObject);
defineLogLevelProperties(someObject);

someObject.logLevel = 'error';
someObject.info(
  severity => 'my info message (not reported since logLevel is error)'
);
someObject.logLevel = 'info';
someObject.info(
  severity => 'my info message (reported since logLevel is now info)'
);

works for ES2015 classes to

import { LogLevelMixin } from 'loglevel-mixin';

const LoggingEnabledClass = LogLevelMixin(
  class BaseClass {
    log(level, message) {
      console.log(`${level} ${message}`);
    }
  }
);

const someObject = new LoggingEnabledClass();

someObject.logLevel = 'error';
someObject.info(
  severity => 'my info message (not reported since logLevel is error)'
);
someObject.logLevel = 'info';
someObject.info(
  severity => 'my info message (reported since logLevel is now info)'
);

install

With npm do:

npm install loglevel-mixin

API

Table of Contents

• Logger
  • Properties
• Loglevel
  • Properties
• defaultLogLevels
• declareLevels
  • Parameters
• defineLoggerMethods
  • Parameters
  • Examples
• LOGLEVEL
• LogLevelMixin
  • Parameters
  • Examples
• defineLogLevelProperties
  • Parameters
  • Properties
• makeLogEvent
  • Parameters

Logger

Type: Function

Properties

• entry Object

Loglevel

Type: Object

Properties

• name string
• priority number

defaultLogLevels

default log levels

• trace
• debug
• info
• notice
• warn
• error
• crit
• alert

declareLevels

Generate the loglevel objects out of a list of log level names.

Parameters

• list Array<string> A list of log level names. The last name in the list will become the one with the highest priority.

Returns Object levels object a hash with all the loglevels. Stored by there name.

defineLoggerMethods

Adds logging methods to an existing object. For each loglevel a method with the name of the log level will be created.

Parameters

• object Object target where to assign properties to
• logLevels Object Hash with all the available loglevels. Stored by there name (optional, default defaultLogLevels)
• theFunction Logger to be added under the loglevel name. This function will only be called if the current loglevel is greater equal the log level of the called logging function. By default a method log(level,message) will be used (optional, default undefined)

Examples

defineLoggerMethods( obj)
obj.info('info entry'); // will redirect to theFunction if obj.loglevel is at least info
obj.error('error entry'); // will redirect to theFunction if obj.loglevel is at least error

Returns undefined

LOGLEVEL

symbol holding the actual logLevel inside of the target object

LogLevelMixin

Parameters

• superclass class class to be extendet
• logLevels Object Object with all the available loglevels. Stored by their name (optional, default defaultLogLevels)
• defaultLogLevel string the default value for the logLevel property (optional, default defaultLogLevels.info)

Examples

import { LogLevelMixin } = from 'loglevel-mixin';
class BaseClass {
  log(level, message) { console.log(`${level} ${message}`); }
}
class LoggingEnabledClass extends LogLevelMixin(BaseClass) {
}

Returns class newly created class ready to be further extendet/used

defineLogLevelProperties

Declares two properties:

Parameters

• object Object target where the properties will be written into
• logLevels Object Hash with all the available loglevels. Stored by there name (optional, default defaultLogLevels)
• defaultLogLevel string the default value for the properties (optional, default defaultLogLevels.info)

Properties

• logLevel string info,error,...
• logLevelPriority number

makeLogEvent

Helper function to aggregate values into a log event

Parameters

• severity string log severity
• arg (string | Object) original log message - level may be overwritten
• args Object? additional values to be merged into the final log event - values have precedence

Returns Object suitable for log event processing

license

BSD-2-Clause