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深拷贝
/**
* 深拷贝
* @param {Object} obj 要拷贝的对象
*/
function deepClone(obj = {}) {if (typeof obj !== 'object' || obj == null) {
// obj 是 null,或者不是对象和数组,间接返回
return obj
}
// 初始化返回后果
let result
if (obj instanceof Array) {result = []
} else {result = {}
}
for (let key in obj) {
// 保障 key 不是原型的属性
if (obj.hasOwnProperty(key)) {
// 递归调用!!!result[key] = deepClone(obj[key])
}
}
// 返回后果
return result
}
class
// 类
class Student {constructor(name, number) {
this.name = name
this.number = number
// this.gender = 'male'
}
sayHi() {
console.log(` 姓名 ${this.name},学号 ${this.number}`
)
// console.log(
// '姓名' + this.name + ',学号' + this.number
// )
}
// study() {//}
}
// 通过类 new 对象 / 实例
const xialuo = new Student('夏洛', 100)
console.log(xialuo.name)
console.log(xialuo.number)
xialuo.sayHi()
const madongmei = new Student('马冬梅', 101)
console.log(madongmei.name)
console.log(madongmei.number)
madongmei.sayHi()
继承
// 父类
class People {constructor(name) {this.name = name}
eat() {console.log(`${this.name} eat something`)
}
}
// 子类
class Student extends People {constructor(name, number) {super(name)
this.number = number
}
sayHi() {console.log(` 姓名 ${this.name} 学号 ${this.number}`)
}
}
// 子类
class Teacher extends People {constructor(name, major) {super(name)
this.major = major
}
teach() {console.log(`${this.name} 传授 ${this.major}`)
}
}
// 实例
const xialuo = new Student('夏洛', 100)
console.log(xialuo.name)
console.log(xialuo.number)
xialuo.sayHi()
xialuo.eat()
// 实例
const wanglaoshi = new Teacher('王老师', '语文')
console.log(wanglaoshi.name)
console.log(wanglaoshi.major)
wanglaoshi.teach()
wanglaoshi.eat()
原型关系
- 每个 class 都有显式原型
- 每个实例都有隐式原型_proto_
- 实例的_proto_指向对应 class 的 prototype
-
基于原型的执行规定
- 获取实例对象的属性或执行办法时
- 先在本身属性和办法寻找
- 如果找不到则主动去隐式原型_proto_中查找
原型链
手写繁难 jQuery
class jQuery {constructor(selector) {const result = document.querySelectorAll(selector)
const length = result.length
for (let i = 0; i < length; i++) {this[i] = result[i]
}
this.length = length
this.selector = selector
}
get(index) {return this[index]
}
each(fn) {for (let i = 0; i < this.length; i++) {const elem = this[i]
fn(elem)
}
}
on(type, fn) {
return this.each(elem => {elem.addEventListener(type, fn, false)
})
}
// 扩大很多 DOM API
}
// 插件
jQuery.prototype.dialog = function (info) {alert(info)
}
//“造轮子”class myJQuery extends jQuery {constructor(selector) {super(selector)
}
// 扩大本人的办法
addClass(className) { }
style(data) {}}
// const $p = new jQuery('p')
// $p.get(1)
// $p.each((elem) => console.log(elem.nodeName))
// $p.on('click', () => alert('clicked'))
正文完