es6 class对象转换es5

在线转换工具 https://babeljs.io/repl

// es6 
class Person {
  name = 'lisi'
  static age = null
  #sex = null
  constructor() {
    this.name = 'zhangsan'
  }
  set() {
    this.name = 'wangwu'
    this.age = 18
    this.#sex = 'nv'
  }
  get() {
    return this.name + this.#sex + '今年' + this.age + '岁'
  }
  static say() {
    console.log(this.name + '说我今年' + this.age + '成年了' + this.#run())
  }
  #run() {
    return '跑起来'
  }
}

var _sex = /*#__PURE__*/ new WeakMap() // 私有属性映射
var _run = /*#__PURE__*/ new WeakSet() // 私有方法映射
// 创建一个自动执行的匿名函数
var Person = /*#__PURE__*/ (function () {
  // 创建构造函数
  function Person() {
    _classCallCheck(this, Person) // 检测类型是否能将类作为函数使用, 使用new关键字创建实例
    _classPrivateMethodInitSpec(this, _run) // 私有方法初始化
    _defineProperty(this, 'name', 'lisi') // 公共属性初始化赋值
    // 私有属性初始化赋值
    _classPrivateFieldInitSpec(this, _sex, {
      writable: true,
      value: null
    })
    this.name = 'zhangsan' // 执行class中constructor构造函数体其他语句
  }
  // 公共方法，静态方法初始化, 接收三个参数，实例，公共方法，静态方法
  _createClass(
    Person,
    [
      {
        key: 'set',
        value: function set() {
          this.name = 'wangwu' // 公共属性赋值
          this.age = 18 // 静态属性赋值
          _classPrivateFieldSet(this, _sex, 'nv') // 私有属性赋值
        }
      },
      {
        key: 'get',
        value: function get() {
          return this.name + _classPrivateFieldGet(this, _sex) + '今年' + this.age + '岁'
        }
      }
    ],
    [
      {
        key: 'say',
        value: function say() {
          console.log(
            this.name + '说我今年' + this.age + '成年了' + _classPrivateMethodGet(this, _run, _run2).call(this)
          )
        }
      }
    ]
  )
  return Person
})()
function _run2() {
  // 私有方法
  return '跑起来'
}
_defineProperty(Person, 'age', null) // 静态属性初始化赋值

function _classCallCheck(instance, Constructor) {
  if (!(instance instanceof Constructor)) {
    throw new TypeError('Cannot call a class as a function')
  }
}

// 类型检测
function _typeof(obj) {
  // const a = (表达式1, 表达式2, ...., 表达式n)
  // 从表达式1开始执行一直到n，最终返回n
  return (
    (_typeof =
      'function' == typeof Symbol && 'symbol' == typeof Symbol.iterator
        ? function (obj) {
            return typeof obj
          }
        : function (obj) {
            return obj && 'function' == typeof Symbol && obj.constructor === Symbol && obj !== Symbol.prototype
              ? 'symbol'
              : typeof obj
          }),
    _typeof(obj) // typeof函数已被改变，并不会递归调用,调用的是前面重新赋值返回的函数
  )
}

// 属性注册
function _defineProperty(obj, key, value) {
  key = _toPropertyKey(key)
  if (key in obj) {
    // 判断是否在当前实例
    Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true })
  } else {
    obj[key] = value
  }
  return obj
}

// 对象key类型检测
function _toPropertyKey(arg) {
  var key = _toPrimitive(arg, 'string')
  return _typeof(key) === 'symbol' ? key : String(key)
}
function _toPrimitive(input, hint) {
  if (_typeof(input) !== 'object' || input === null) return input
  var prim = input[Symbol.toPrimitive]
  if (prim !== undefined) {
    var res = prim.call(input, hint || 'default')
    if (_typeof(res) !== 'object') return res
    throw new TypeError('@@toPrimitive must return a primitive value.')
  }
  return (hint === 'string' ? String : Number)(input)
}
// 私有属性注册
function _classPrivateFieldInitSpec(obj, privateMap, value) {
  _checkPrivateRedeclaration(obj, privateMap)
  privateMap.set(obj, value)
}
// 设置私有属性
function _classPrivateFieldSet(receiver, privateMap, value) {
  var descriptor = _classExtractFieldDescriptor(receiver, privateMap, 'set')
  _classApplyDescriptorSet(receiver, descriptor, value)
  return value
}
// 判断映射表中是否存在这个映射，存在即返回，否则抛错处理
function _classExtractFieldDescriptor(receiver, privateMap, action) {
  if (!privateMap.has(receiver)) {
    throw new TypeError('attempted to ' + action + ' private field on non-instance')
  }
  return privateMap.get(receiver)
}
// 将最新的值更新到映射表中
function _classApplyDescriptorSet(receiver, descriptor, value) {
  if (descriptor.set) {
    descriptor.set.call(receiver, value)
  } else {
    if (!descriptor.writable) {
      throw new TypeError('attempted to set read only private field')
    }
    descriptor.value = value
  }
}
// 获取属性映射图
function _classPrivateFieldGet(receiver, privateMap) {
  var descriptor = _classExtractFieldDescriptor(receiver, privateMap, 'get')
  return _classApplyDescriptorGet(receiver, descriptor)
}
// 获取映射值返回
function _classApplyDescriptorGet(receiver, descriptor) {
  if (descriptor.get) {
    return descriptor.get.call(receiver)
  }
  return descriptor.value
}

// 方法注册
function _createClass(Constructor, protoProps, staticProps) {
  if (protoProps) _defineProperties(Constructor.prototype, protoProps) // 公共方法注册
  if (staticProps) _defineProperties(Constructor, staticProps) // 静态方法注册
  Object.defineProperty(Constructor, 'prototype', { writable: false })
  return Constructor
}
// 对公共、静态方法遍历注册
function _defineProperties(target, props) {
  for (var i = 0; i < props.length; i++) {
    var descriptor = props[i]
    descriptor.enumerable = descriptor.enumerable || false
    descriptor.configurable = true
    if ('value' in descriptor) descriptor.writable = true
    Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor)
  }
}
// 私有方法注册
function _classPrivateMethodInitSpec(obj, privateSet) {
  _checkPrivateRedeclaration(obj, privateSet)
  privateSet.add(obj)
}
// 是否存在私有方法，抛错处理
function _classPrivateMethodGet(receiver, privateSet, fn) {
  if (!privateSet.has(receiver)) {
    throw new TypeError('attempted to get private field on non-instance')
  }
  return fn
}

// 检测是否重复注册
function _checkPrivateRedeclaration(obj, privateCollection) {
  if (privateCollection.has(obj)) {
    throw new TypeError('Cannot initialize the same private elements twice on an object')
  }
}