对于JavaScript继承你到底了解多少

function Parent(name){
    this.name = name || 'xt',
    this.arr = [1]
}
function Son(age){
    this.age = age
}
Parent.prototype.say = function() { //将需要复⽤、共享的⽅法定义在⽗类原型上
    console.log('hello');
}
Son.prototype = new Parent()
let s1 = new Son(18)
let s2 = new Son(19)
console.log(s1.say() === s2.say()); //true
console.log(s1.name,s1.age); //xt 18
console.log(s2.name,s2.age); //xt 19
s1.arr.push(2)
console.log(s1.arr,s2.arr); // [ 1, 2 ] [ 1, 2 ]

function Parent(name) {
    this.name = name;
    this.arr = [1],
    this.say = function() { console.log('hello') }
}
function Son(name, age) {
    Parent.call(this, name) // 拷⻉了⽗类的实例属性和⽅法
    this.age = age
}
let s1 = new Son('小谭', 18)
let s2 = new Son('小明', 19)
console.log(s1.say === s2.say) //false ⽅法不能复⽤ ⽅法是独⽴，不是共享的
console.log(s1.name, s1.age); //小谭 18
console.log(s2.name, s2.age); //小明 19
s1.arr.push(2)
console.log(s1.arr, s2.arr); // [ 1, 2 ] [ 1 ]

function Parent(name) {
    this.name = 'xt';
    this.arr = [1]
}
function object(obj){
    function F(){}
    F.prototype = obj;
    return new F();
  }
let s1 = new Parent(object)
s1.name = '小明'
s1.arr.push(2)
let s2 = new Parent(object)
console.log(s1.name,s2.name); // 小明 xt
console.log(s1.arr, s2.arr); //[ 1, 2 ] [ 1 ]

function Parent(name) {
    this.name = 'xt';
    this.arr = [1]
}
function object(obj){
    function F(){}
    F.prototype = obj;
    return new F();
  }
let Son = new Parent()
function addobject(obj){
    var add = object(obj)
    add.name = '小白'
    return add
}
var s1 = addobject(Son)
console.log(s1.name); //小白

function Parent(name) {
    this.name = name;
    this.arr = [1]
}
Parent.prototype.say = function () { console.log('hello') }
function Son(name, age) {
    Parent.call(this, name) // 二次
    this.age = age
}
Parent.prototype = new Son() // 一次
let s1 = new Son('小谭', 18)
let s2 = new Son('小明', 19)
console.log(s1.say === s2.say) // true
console.log(s1.name, s1.age); //小谭 18
console.log(s2.name, s2.age); //小明 19
s1.arr.push(2)
console.log(s1.arr, s2.arr); // [ 1, 2 ] [ 1 ] 不共享⽗类的引⽤属性，

function Parent(name){
    this.name = name || 'xt',
    this.arr = [1]
}
function Son(name,age){
    Parent.call(this,name) // 核⼼
    this.age = age
}
Parent.prototype.say = function() {  
    console.log('hello');
}
Son.prototype = Object.create(Parent.prototype) // 核心 通过创建中间对象，⼦类原型和⽗类原型，就会隔离开。
Son.prototype.constructor = Son
let p1 = new Parent()

let s1 = new Son("小红",18)
let s2 = new Son("小黑",19)
console.log(p1.constructor); //[Function: Parent]
console.log(s1.constructor); // [Function: Son]
console.log(s1.say() === s2.say()); //true
console.log(s1.name,s1.age); // 小红 18
console.log(s2.name,s2.age); //小黑 19
s1.arr.push(2)
console.log(s1.arr,s2.arr); // [ 1, 2 ] [ 1, 2 ]