构造类以及继承
构造函数方法
function Person(name) { this.name = name}Person.prototype.species = 'human'Person.prototype.sayName = { alert(this.name)}let person = new Person()person.sayName() - 该种方式下的继承
（1）封装一个函数
function extend (child, Parent) { let F = function(){} F.prototype = Parent.prototype child.prototype = new F() child.prototype.constructor = child}function Man (name) {this.name = name}extend(Man, Person)let man1 = new Man('ziv')console.log(man1.species) // human （2）绑定
function Man () { Person.call(this, arguments) // call,apply,bind} （3）复制继承
function Man () {}for (let prop in Person.prototype) { // Man.prototype[prop] = Person.prototype[prop]}Man.prototype.constructor = Man 对象创建方法
let Person = { name: 'michal', sayName: function() { alert(this.name) }}let person = Object.create(Person)person.sayName() class类的实现
class Point { constructor(x, y) { this.x = x this.y = y } toString() { return `( ${this.x} ,${this.y} )` }} - 该种方式下的继承
class micPoint extends Point(x, y, z) { constructor() { super(x, y) this.z = z } toString () { return this.z + '' + super.toString() } }let point = new Point(2, 3) 极简主义法
- 实现一个类
let Animal = { createNew: function() { let animal = {} animal.name = 'animal' animal.sleep = function() {console.log('睡觉')} return animal }}let animal1 = Animal.createNew()animal1.sleep() // 睡觉 - 类的私有属性和方法
let Cat = { createNew: function() { let cat = {} // 在createNew()方法中，只要不是定义在cat对象上的方法和属性，都是私有的 let sound = 'miaomiao' // 该sound变量只能通过公有方法makeSound()来读取 cat.makeSound = function (){console.log(sound)} return cat }}let cat2 = Cat.createNew()console.log(cat2.sound) // undefined - 类的数据共享
let Cat = { sound: '喵喵' createNew: function(){ let cat = {} cat.makeSound = function(){console.log(Cat.sound)} cat.changeSound = function(x){Cat.sound = x} return cat }}let cat1 = Cat.createNew()let cat2 = Cat.createNew()cat1.makeSound() // 喵喵cat2.changeSound('汪汪') // 修改了共享的数据，另一个实例对象也会受到影响cat1.makeSound() // 汪汪 - 该种方式下的继承实现
let Cat = { createNew: function() { let cat = Animal.createNew() cat.name = 'miao' cat.makeSound = function () {console.log('喵喵')} return cat }}let cat1 = Cat.createNew() // 该实例会继承Cat和Animal类cat1.sleep() // 睡觉