add hw2

node_modules/pino/lib/levels.js

@@ -0,0 +1,241 @@
+'use strict'
+/* eslint no-prototype-builtins: 0 */
+const {
+  lsCacheSym,
+  levelValSym,
+  useOnlyCustomLevelsSym,
+  streamSym,
+  formattersSym,
+  hooksSym,
+  levelCompSym
+} = require('./symbols')
+const { noop, genLog } = require('./tools')
+const { DEFAULT_LEVELS, SORTING_ORDER } = require('./constants')
+
+const levelMethods = {
+  fatal: (hook) => {
+    const logFatal = genLog(DEFAULT_LEVELS.fatal, hook)
+    return function (...args) {
+      const stream = this[streamSym]
+      logFatal.call(this, ...args)
+      if (typeof stream.flushSync === 'function') {
+        try {
+          stream.flushSync()
+        } catch (e) {
+          // https://github.com/pinojs/pino/pull/740#discussion_r346788313
+        }
+      }
+    }
+  },
+  error: (hook) => genLog(DEFAULT_LEVELS.error, hook),
+  warn: (hook) => genLog(DEFAULT_LEVELS.warn, hook),
+  info: (hook) => genLog(DEFAULT_LEVELS.info, hook),
+  debug: (hook) => genLog(DEFAULT_LEVELS.debug, hook),
+  trace: (hook) => genLog(DEFAULT_LEVELS.trace, hook)
+}
+
+const nums = Object.keys(DEFAULT_LEVELS).reduce((o, k) => {
+  o[DEFAULT_LEVELS[k]] = k
+  return o
+}, {})
+
+const initialLsCache = Object.keys(nums).reduce((o, k) => {
+  o[k] = '{"level":' + Number(k)
+  return o
+}, {})
+
+function genLsCache (instance) {
+  const formatter = instance[formattersSym].level
+  const { labels } = instance.levels
+  const cache = {}
+  for (const label in labels) {
+    const level = formatter(labels[label], Number(label))
+    cache[label] = JSON.stringify(level).slice(0, -1)
+  }
+  instance[lsCacheSym] = cache
+  return instance
+}
+
+function isStandardLevel (level, useOnlyCustomLevels) {
+  if (useOnlyCustomLevels) {
+    return false
+  }
+
+  switch (level) {
+    case 'fatal':
+    case 'error':
+    case 'warn':
+    case 'info':
+    case 'debug':
+    case 'trace':
+      return true
+    default:
+      return false
+  }
+}
+
+function setLevel (level) {
+  const { labels, values } = this.levels
+  if (typeof level === 'number') {
+    if (labels[level] === undefined) throw Error('unknown level value' + level)
+    level = labels[level]
+  }
+  if (values[level] === undefined) throw Error('unknown level ' + level)
+  const preLevelVal = this[levelValSym]
+  const levelVal = this[levelValSym] = values[level]
+  const useOnlyCustomLevelsVal = this[useOnlyCustomLevelsSym]
+  const levelComparison = this[levelCompSym]
+  const hook = this[hooksSym].logMethod
+
+  for (const key in values) {
+    if (levelComparison(values[key], levelVal) === false) {
+      this[key] = noop
+      continue
+    }
+    this[key] = isStandardLevel(key, useOnlyCustomLevelsVal) ? levelMethods[key](hook) : genLog(values[key], hook)
+  }
+
+  this.emit(
+    'level-change',
+    level,
+    levelVal,
+    labels[preLevelVal],
+    preLevelVal,
+    this
+  )
+}
+
+function getLevel (level) {
+  const { levels, levelVal } = this
+  // protection against potential loss of Pino scope from serializers (edge case with circular refs - https://github.com/pinojs/pino/issues/833)
+  return (levels && levels.labels) ? levels.labels[levelVal] : ''
+}
+
+function isLevelEnabled (logLevel) {
+  const { values } = this.levels
+  const logLevelVal = values[logLevel]
+  return logLevelVal !== undefined && this[levelCompSym](logLevelVal, this[levelValSym])
+}
+
+/**
+ * Determine if the given `current` level is enabled by comparing it
+ * against the current threshold (`expected`).
+ *
+ * @param {SORTING_ORDER} direction comparison direction "ASC" or "DESC"
+ * @param {number} current current log level number representation
+ * @param {number} expected threshold value to compare with
+ * @returns {boolean}
+ */
+function compareLevel (direction, current, expected) {
+  if (direction === SORTING_ORDER.DESC) {
+    return current <= expected
+  }
+
+  return current >= expected
+}
+
+/**
+ * Create a level comparison function based on `levelComparison`
+ * it could a default function which compares levels either in "ascending" or "descending" order or custom comparison function
+ *
+ * @param {SORTING_ORDER | Function} levelComparison sort levels order direction or custom comparison function
+ * @returns Function
+ */
+function genLevelComparison (levelComparison) {
+  if (typeof levelComparison === 'string') {
+    return compareLevel.bind(null, levelComparison)
+  }
+
+  return levelComparison
+}
+
+function mappings (customLevels = null, useOnlyCustomLevels = false) {
+  const customNums = customLevels
+    /* eslint-disable */
+    ? Object.keys(customLevels).reduce((o, k) => {
+        o[customLevels[k]] = k
+        return o
+      }, {})
+    : null
+    /* eslint-enable */
+
+  const labels = Object.assign(
+    Object.create(Object.prototype, { Infinity: { value: 'silent' } }),
+    useOnlyCustomLevels ? null : nums,
+    customNums
+  )
+  const values = Object.assign(
+    Object.create(Object.prototype, { silent: { value: Infinity } }),
+    useOnlyCustomLevels ? null : DEFAULT_LEVELS,
+    customLevels
+  )
+  return { labels, values }
+}
+
+function assertDefaultLevelFound (defaultLevel, customLevels, useOnlyCustomLevels) {
+  if (typeof defaultLevel === 'number') {
+    const values = [].concat(
+      Object.keys(customLevels || {}).map(key => customLevels[key]),
+      useOnlyCustomLevels ? [] : Object.keys(nums).map(level => +level),
+      Infinity
+    )
+    if (!values.includes(defaultLevel)) {
+      throw Error(`default level:${defaultLevel} must be included in custom levels`)
+    }
+    return
+  }
+
+  const labels = Object.assign(
+    Object.create(Object.prototype, { silent: { value: Infinity } }),
+    useOnlyCustomLevels ? null : DEFAULT_LEVELS,
+    customLevels
+  )
+  if (!(defaultLevel in labels)) {
+    throw Error(`default level:${defaultLevel} must be included in custom levels`)
+  }
+}
+
+function assertNoLevelCollisions (levels, customLevels) {
+  const { labels, values } = levels
+  for (const k in customLevels) {
+    if (k in values) {
+      throw Error('levels cannot be overridden')
+    }
+    if (customLevels[k] in labels) {
+      throw Error('pre-existing level values cannot be used for new levels')
+    }
+  }
+}
+
+/**
+ * Validates whether `levelComparison` is correct
+ *
+ * @throws Error
+ * @param {SORTING_ORDER | Function} levelComparison - value to validate
+ * @returns
+ */
+function assertLevelComparison (levelComparison) {
+  if (typeof levelComparison === 'function') {
+    return
+  }
+
+  if (typeof levelComparison === 'string' && Object.values(SORTING_ORDER).includes(levelComparison)) {
+    return
+  }
+
+  throw new Error('Levels comparison should be one of "ASC", "DESC" or "function" type')
+}
+
+module.exports = {
+  initialLsCache,
+  genLsCache,
+  levelMethods,
+  getLevel,
+  setLevel,
+  isLevelEnabled,
+  mappings,
+  assertNoLevelCollisions,
+  assertDefaultLevelFound,
+  genLevelComparison,
+  assertLevelComparison
+}