pino/lib/proto.js

'use strict'

/* eslint no-prototype-builtins: 0 */

const { EventEmitter } = require('events')
const SonicBoom = require('sonic-boom')
const flatstr = require('flatstr')
const {
  lsCacheSym,
  levelValSym,
  setLevelSym,
  getLevelSym,
  chindingsSym,
  parsedChindingsSym,
  mixinSym,
  asJsonSym,
  writeSym,
  timeSym,
  timeSliceIndexSym,
  streamSym,
  serializersSym,
  formattersSym,
  useOnlyCustomLevelsSym,
  needsMetadataGsym
} = require('./symbols')
const {
  getLevel,
  setLevel,
  isLevelEnabled,
  mappings,
  initialLsCache,
  genLsCache,
  assertNoLevelCollisions
} = require('./levels')
const {
  asChindings,
  asJson,
  buildFormatters
} = require('./tools')
const {
  version
} = require('./meta')

// note: use of class is satirical
// https://github.com/pinojs/pino/pull/433#pullrequestreview-127703127
const constructor = class Pino {}
const prototype = {
  constructor,
  child,
  bindings,
  setBindings,
  flush,
  isLevelEnabled,
  version,
  get level () { return this[getLevelSym]() },
  set level (lvl) { this[setLevelSym](lvl) },
  get levelVal () { return this[levelValSym] },
  set levelVal (n) { throw Error('levelVal is read-only') },
  [lsCacheSym]: initialLsCache,
  [writeSym]: write,
  [asJsonSym]: asJson,
  [getLevelSym]: getLevel,
  [setLevelSym]: setLevel
}

Object.setPrototypeOf(prototype, EventEmitter.prototype)

// exporting and consuming the prototype object using factory pattern fixes scoping issues with getters when serializing
module.exports = function () {
  return Object.create(prototype)
}

const resetChildingsFormatter = bindings => bindings
function child (bindings) {
  if (!bindings) {
    throw Error('missing bindings for child Pino')
  }
  const serializers = this[serializersSym]
  const formatters = this[formattersSym]
  const instance = Object.create(this)
  if (bindings.hasOwnProperty('serializers') === true) {
    instance[serializersSym] = Object.create(null)

    /* eslint no-var: off */
    for (var k in serializers) {
      instance[serializersSym][k] = serializers[k]
    }
    const parentSymbols = Object.getOwnPropertySymbols(serializers)
    for (var i = 0; i < parentSymbols.length; i++) {
      const ks = parentSymbols[i]
      instance[serializersSym][ks] = serializers[ks]
    }

    for (var bk in bindings.serializers) {
      instance[serializersSym][bk] = bindings.serializers[bk]
    }
    const bindingsSymbols = Object.getOwnPropertySymbols(bindings.serializers)
    for (var bi = 0; bi < bindingsSymbols.length; bi++) {
      const bks = bindingsSymbols[bi]
      instance[serializersSym][bks] = bindings.serializers[bks]
    }
  } else instance[serializersSym] = serializers
  if (bindings.hasOwnProperty('formatters')) {
    const { level, bindings: chindings, log } = bindings.formatters
    instance[formattersSym] = buildFormatters(
      level || formatters.level,
      chindings || resetChildingsFormatter,
      log || formatters.log
    )
  } else {
    instance[formattersSym] = buildFormatters(
      formatters.level,
      resetChildingsFormatter,
      formatters.log
    )
  }
  if (bindings.hasOwnProperty('customLevels') === true) {
    assertNoLevelCollisions(this.levels, bindings.customLevels)
    instance.levels = mappings(bindings.customLevels, instance[useOnlyCustomLevelsSym])
    genLsCache(instance)
  }
  instance[chindingsSym] = asChindings(instance, bindings)
  const childLevel = bindings.level || this.level
  instance[setLevelSym](childLevel)

  return instance
}

function bindings () {
  const chindings = this[chindingsSym]
  const chindingsJson = `{${chindings.substr(1)}}` // at least contains ,"pid":7068,"hostname":"myMac"
  const bindingsFromJson = JSON.parse(chindingsJson)
  delete bindingsFromJson.pid
  delete bindingsFromJson.hostname
  return bindingsFromJson
}

function setBindings (newBindings) {
  const chindings = asChindings(this, newBindings)
  this[chindingsSym] = chindings
  delete this[parsedChindingsSym]
}

function write (_obj, msg, num) {
  const t = this[timeSym]()
  const mixin = this[mixinSym]
  const objError = _obj instanceof Error
  let obj

  if (_obj === undefined || _obj === null) {
    obj = mixin ? mixin({}) : {}
  } else {
    obj = Object.assign(mixin ? mixin(_obj) : {}, _obj)
    if (!msg && objError) {
      msg = _obj.message
    }

    if (objError) {
      obj.stack = _obj.stack
      if (!obj.type) {
        obj.type = 'Error'
      }
    }
  }

  const s = this[asJsonSym](obj, msg, num, t)

  const stream = this[streamSym]
  if (stream[needsMetadataGsym] === true) {
    stream.lastLevel = num
    stream.lastObj = obj
    stream.lastMsg = msg
    stream.lastTime = t.slice(this[timeSliceIndexSym])
    stream.lastLogger = this // for child loggers
  }
  if (stream instanceof SonicBoom) stream.write(s)
  else stream.write(flatstr(s))
}

function flush () {
  const stream = this[streamSym]
  if ('flush' in stream) stream.flush()
}