收藏了也不看的JavaScript,面向对象程序设计(下)!

今天接着上一篇,昨天其实因为这周太累了,赶着上线每天加班。昨天12点的时候,脖子都开始疼了。好了不废话了开始了~

继承

继承:子类继承父类中的属性和方法 , 这些属性和方法在子类中不需要实现过程

继承的种类:

单继承:一个子类只拥有一个父类

多继承:一个子类可以拥有多个父类

原型链

这里真的呼吁学js的小伙伴一定要看红宝书哦。

function SuperType(){

this.property = true;

}

SuperType.prototype.getSuperValue = function(){

};

function SubType(){

this.subproperty = false;

}

//SuperType

SubType.prototype = new SuperType();

SubType.prototype.getSubValue = function (){

return this.subproperty;

};

var instance = new SubType();

alert(instance.getSuperValue()); //true

原型链的问题

function SuperType(){

this.colors = ["red", "blue", "green"];

alert(instance1.colors); //"red,blue,green,black"

}

function SubType(){}

//SuperType

SubType.prototype = new SuperType();

var instance1 = new SubType();

instance1.colors.push("black");

var instance2 = new SubType(); alert(instance2.colors); //"red,blue,green,black"

原型继承

var person = {

name: "Nicholas",

friends: ["Shelby", "Court", "Van"]

};

var anotherPerson = object(person);

anotherPerson.name = "Greg";

anotherPerson.friends.push("Rob");

var yetAnotherPerson = object(person);

yetAnotherPerson.name = "Linda";

yetAnotherPerson.friends.push("Barbie");

alert(person.friends); //"Shelby,Court,Van,Rob,Barbie"

var person = {

name: "Nicholas",

friends: ["Shelby", "Court", "Van"]

};

var anotherPerson = Object.create(person);

anotherPerson.name = "Greg";

anotherPerson.friends.push("Rob");

var yetAnotherPerson = Object.create(person);

yetAnotherPerson.name = "Linda";

yetAnotherPerson.friends.push("Barbie");

alert(person.friends); //"Shelby,Court,Van,Rob,Barbie"

继承方法

继承方式一、通过改变构造函数(父类)的执行环境 ---在子类中添加一个特殊属性,这个属性值指向父类

function Father(){

this.money = 999999;

this.eat = function(){

console.log("吃肉");

}

this.drink = function(){

console.log("喝酒");

}

}

function Son(){

this.parent = Father; //为子类添加一个特有的属性 改变父类的执行环境 类似:this.parent = function (){....}

this.parent();//改变了执行环境

}

var son = new Son();

继承方式二、通过call方法实现

call方法使用:

父类.call(子类[,子类继承父类的属性]);

function Father(firstname){

this.firstname = firstname;

this.money = 200000000;

this.drink = function(){

console.log("喝酒");

}

this.dance = function(){

console.log("跳舞");

}

}

function Son(firstname){

Father.call(this,firstname );

}

继承方式三、通过apply继承

apply使用方法:

父类.apply(子类对象,数组) 数组中存储的是从父类继承过来的属性

function xiaomi5(price,size,memsize){

this.price = price;

this.size = size;

this.memsize = memsize;

this.phoneCall = function(){

console.log("打电话");

}

this.sendMessage = function(){

console.log("发短信");

}

}

function xiaomi5Plus(price,size,memsize,color){

this.color = color;//特有属性

//xiaomi5.apply(this,[price,size,memsize]);

xiaomi5.apply(this,arguments);//通过arguments接收

this.playMusic = function(){

return "播放音乐";

}

this.photo = function(){

console.log("照相");

}

}

var xm = new xiaomi5Plus(789,7,64,"white");

console.log(xm);

组合继承

这里要摘出来说一下

通过apply或call继承实例属性

通过原型方式 继承 原型方法

function Father(money,firstname){

this.money = money;

this.firstname = firstname;

}

Father.prototype.dance = function(){

console.log("跳舞");

}

Father.prototype.sleep= function(){

console.log("睡觉");

}

function Son(money,firstname){

Father.call(this,money,firstname);

}

//原型继承

Son.prototype = new Father();

var son = new Son("200000","王");

son.dance();

function SuperType(name){

this.name = name;

this.colors = ["red", "blue", "green"];

}

SuperType.prototype.sayName = function(){

alert(this.name);

JavaScript instanceof isPrototypeOf()

function object(o){

function F(){}

object() object()13

};

function SubType(name, age){

//SuperType.call(this, name);

this.age = age;

}

//

SubType.prototype = new SuperType(); SubType.prototype.constructor = SubType; SubType.prototype.sayAge = function(){

alert(this.age);

};

var instance1 = new SubType("Nicholas", 29);

instance1.colors.push("black");

alert(instance1.colors);

instance1.sayName();

instance1.sayAge();

//"red,blue,green,black"

//"Nicholas";

//29

var instance2 = new SubType("Greg", 27);

alert(instance2.colors);//"red,blue,green"

instance2.sayName();//"Greg";

instance2.sayAge();//27

寄生组合式继承

这个继承方式,如果不看红宝书的情况下,你很少会知道有这个方法。我曾经面试用这个方法装了一发哈哈哈

function SuperType(name){

this.name = name;

this.colors = ["red", "blue", "green"];

}

SuperType.prototype.sayName = function(){

alert(this.name);

};

function SubType(name, age){

SuperType.call(this, name);

this.age = age;

}

SubType.prototype = new SuperType();

SubType.prototype.constructor = SubType;

SubType.prototype.sayAge = function(){

alert(this.age);

};

function inheritPrototype(subType, superType){

var prototype = object(superType.prototype);

prototype.constructor = subType;

subType.prototype = prototype;

}

function SuperType(name){

this.name = name;

this.colors = ["red", "blue", "green"];

}

SuperType.prototype.sayName = function(){

alert(this.name);

};

function SubType(name, age){

SuperType.call(this, name);

this.age = age;

}

inheritPrototype(SubType, SuperType);

SubType.prototype.sayAge = function(){

alert(this.age);

}

总结

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你都看到这了,不点个关注就过分了哈~

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