@felixpy/logger v0.2.0

logger

A simple javascript logger for web developers.

Installation

Using NPM

npm i @felixpy/logger --save

Using CDN

<script src="https://unpkg.com/@felixpy/logger"></script>

Quick Start

const logger = new Logger({
  name: 'LoggerName',
  config: {
    separator: '>>>',
    dateFormatter: function (date) {
      return date.toISOString()
    }
  }
})

logger.log('MethodName', 'Hello Logger!')
// [2018-02-25T14:36:49.287Z] [LOG] [LoggerName->MethodName] >>> Hello Logger!

Constructor

Using new Logger(options) to create an instance.

options.name

Type: String

Optional logger name, by default it will be Logger#{id}.

options.config

Type: Object

Custom configuration of logger, these are available keys, none is required:

{
  // The minimum log level to show,
  // Available values: ALL, DEBUG, LOG, INFO, WARN, ERROR, OFF.
  level: 'LOG',

  // Prefix pattern:
  //   %t: date
  //   %p: priority
  //   %c: logger name
  //   %m: method name
  prefix: '[%t] [%p] [%c->%m]',

  // The separator symbol between prefix and messages.
  separator: '-',

  // Callback function to format date.
  dateFormatter (d) {
    return d.toLocaleString()
  },

  // Appenders, it can be built-in appender name or your own appender definition.
  appenders: ['console']
}

options.config.appenders

Type: String | Function | Object | Array<String | Function | Object>

Normally, you shold specify an object appender option like this:

{
  // built-in appender name
  type: 'console'
}
// or
{
  /**
   * custom appender callback
   * @param {string} level - log level
   * @param {string} args - message arguments
   */
  handler: function (level, args) {}
}

Also you can simply specify a string as built-in appender name or a function as appender callback.

When you want use multiple appenders, you just need put them in an array.

Instance Methods

Each instance of logger will have these methods:

logger.debug(methodName, ...args)

Log with DEBUG priority. See logger.log.

logger.log(methodName, ...args)

Log with LOG priority, example:

logger.log('Save', 'Parameters: ', '{"name":"foobar"}')
// [2018/2/26 下午11:09:54] [LOG] [ExampleLogger->Save] - Parameters:  {"name":"foobar"}

Note: When only passing one argument, the method name will be ignored. Example:

logger.log('Some magic messages')
// [2018/2/26 下午11:08:44] [LOG] [ExampleLogger->?] - Some magic messages

logger.info(methodName, ...args)

Log with INFO priority. See logger.log.

logger.warn(methodName, ...args)

Log with WARN priority. See logger.log.

logger.error(methodName, ...args)

Log with ERROR priority. See logger.log.

logger.setLevel(level)

Set minimum level to show logs, example:

logger.setLevel('INFO')

logger.setPrefix(prefix)

Set prefix pattern of logger, example:

logger.setPrefix('[Date->%t] [Priority->%p] [%c->%m]')

logger.setSeparator(separator)

Set separator of logger, example:

logger.setSeparator('>>>')

logger.setDateFormatter(dateFormatter)

Set date formatter of logger, example:

logger.setDateFormatter(function(date) {
  return date.toGMTString()
})

logger.setAppender(appenders)

Set appenders of logger, example:

const myAppender = {
  handler: function (level, args) { /* ... */ }
}

logger.setAppender(['console', myAppender])

Global API

Logger.get(options)

Return an single instance by specified options.

License

MIT

Copyright (c) 2018, Felix Yang