Refactor lib, export loglevel's Logger subclass

Author: LeartS

lib/log.js

@@ -4,10 +4,6 @@ const logLevel = require('loglevel')
 const chalk = require('chalk')
 const prefix = require('loglevel-plugin-prefix')
 
-const getKeyByValue = (object, value) => {
-  return Object.keys(object).find(key => object[key] === value)
-}
-
 const colors = Object.freeze({
   TRACE: chalk.magenta,
   DEBUG: chalk.cyan,
@@ -16,42 +12,64 @@ const colors = Object.freeze({
   ERROR: chalk.red
 })
 
-const logConfiguration = {
-  // template: '[%t] %l %n:',
-  format(level, name, timestamp) {
-    return `${chalk.gray(`[${timestamp}]`)} ${colors[level.toUpperCase()](level)} ${chalk.green(`${name}:`)}`
-  },
-  timestampFormatter: () => {
-    const tzOffset = (new Date()).getTimezoneOffset() * 60000 // offset in milliseconds
-    const localISOTime = (new Date(Date.now() - tzOffset)).toISOString().slice(0, -1) // => '2015-01-26T06:40:36.181'
-    return localISOTime
-  }
+const defaultTimestampFormatter = (date) => {
+  const tzOffset = date.getTimezoneOffset() * 60000 // offset in milliseconds
+  const localISOTime = (new Date(date - tzOffset)).toISOString().slice(0, -1) // => '2015-01-26T06:40:36.181'
+  return localISOTime
+}
+
+const defaultNameFormatter = (name) => {
+  return chalk.green(name)
+}
+
+const defaultLevelFormatter = (level) => {
+  return colors[level.toUpperCase()](level.toUpperCase())
 }
 
-module.exports.levels = logLevel.levels
+const defaultTemplate = '[%t] %l [%n]:'
 
-module.exports.monkLog = ({ name = '', level = logLevel.levels.DEBUG, wrap = ['[', ']'] } = {}) => {
-  if (!Array.isArray(wrap)) {
-    wrap = ['[', ']']
+const defaultOptions = {
+  levelFormatter: defaultLevelFormatter,
+  timestampFormatter: defaultTimestampFormatter,
+  nameFormatter: defaultNameFormatter,
+  template: defaultTemplate,
+  level: 'WARN'
+}
+
+const _loggersByName = {}
+
+class MonkLogger extends logLevel.constructor {
+  constructor (name, level, options) {
+    super(name, level)
+    this.options = {...defaultOptions}
+    this.configure(options)
   }
 
-  if (wrap.length !== 2) {
-    throw new Error(`Wrong wrap params, expected 2 got ${wrap.length} elements`)
+  configure (options, reset = false) {
+    this.options = {
+      ...(reset ? defaultOptions : this.options),
+      ...options,
+    }
+    this.setLevel(this.options.level)
+    prefix.apply(this, this.options)
   }
 
-  let logger
-  if (name) {
-    name = `${wrap[0]}${name}${wrap[1]}`
-    logger = logLevel.getLogger(name)
-  } else {
-    // root name is nasty
-    logger = logLevel.getLogger('monk-log')
+  getLogger (name, level, options) {
+    if (typeof name !== "string" || name === "") {
+      throw new TypeError("You must supply a name when creating a logger.")
+    }
+    let logger = _loggersByName[name]
+    if (!logger) {
+      logger = _loggersByName[name] = new MonkLogger(
+        name, level, {...this.options, ...options})
+    }
+    return logger
   }
+}
 
-  prefix.reg(logLevel)
-  prefix.apply(logger, logConfiguration)
-  logger.setLevel(level)
-  logger.info(`Set log level to ${getKeyByValue(logger.levels, level)}`)
+prefix.reg(logLevel)
 
-  return logger
-}
+const defaultLogger = new MonkLogger('root')
+defaultLogger.getLoggers = () => _loggersByName
+
+module.exports = defaultLogger