本次总结一些学习demo,包括
- 函数作用域以及闭包
- 基本类型以及引用类型
- 面向对象之创建对象三种基本方式
//函数作用域
function outer(){
console.log("outer"+this);
function inner1(){
console.log("inner1"+this);
}
function inner2(){
console.log("inner2"+this);
}
inner1();
inner2();
}
outer();
//闭包
function outer(){
var target = "outer";
function inner(){
console.log("get outer"+target);
}
return inner;
}
var outerOne =outer();
outerOne();
//基本类型和引用类型
var a = 5;
var b = a;
b=4;
console.log(a);
var o=new Object();
o.name = "韩梅梅"
var o2=o;
o2.name = "李雷";
console.log(o.name);
//对象中的基本类型和引用类型
var o1 = new Object();
var o2 = o1;
o1.name = "韩梅梅";
console.log(o2.name);
//参数只能按值传递
function test(obj){
obj.name = "颜色不一样的烟火"
console.log(obj.name);
}
var onjTest={
name: "我就是我"
}
test(onjTest);
console.log(onjTest.name+"姨?怎么被改变了?看下面");
function test2(obj){
obj.name ="瞅啥瞅";
obj=new Object();
obj.name = "瞅你咋地";
}
test2(onjTest);
console.log(onjTest.name+"姨?是的,传的不是实体的引用,而是对象在堆中的地址,也就是传值,根据值来在堆中有相应的引用");
//识别自定义的对象类型incetanceof
//使用工厂模式
function Toy(type){
var obj=new Object();
obj.type =type;
obj.mackYouHappy = function(){
console.log("笑一笑"+obj.type);
}
return obj;//很重要
}
var soft = Toy("毛绒");
var car = Toy("车模");
soft.mackYouHappy();
car.mackYouHappy();
console.log(soft instanceof Toy);
console.log(soft instanceof Object);
console.log(soft instanceof Function);
console.log("到底是什么类型呐,老衲不能接受");
//使用构造函数
function ToyObj(type){
this.type = type;
this.mackYouHappy = function(){
console.log("this"+this);
console.log("笑一笑"+this.type);
}
}
var softObj = new ToyObj("毛绒");
var carObj = new ToyObj("车模");
softObj.mackYouHappy();
carObj.mackYouHappy();
console.log(softObj instanceof ToyObj);
console.log(softObj instanceof Object);
console.log(softObj instanceof Function);
console.log("诶呦,ToyObj可以判断啦,重复定义了mackYouHappy()Function对象,老衲不能接受");
//原型模式
function ToyProto(){
}
ToyProto.prototype.type="玩具";
ToyProto.prototype.mackYouHappy = function(){
console.log("笑一笑"+this.type);
}
var softProto = new ToyProto();
//进行独有属性的设置
softProto.type = "毛绒";
var carProto = new ToyProto();
softProto.mackYouHappy();
carProto.mackYouHappy();
console.log(softProto instanceof ToyProto);
console.log(softProto instanceof Object);
console.log(softProto instanceof Function);
console.log("原型以及其它函数模式,老衲来日再战");
本次在上次的基础上练习三种组合的创建对象方法以及一种继承原型链,
后续将附上更多继承写法及其优劣,以及常见的用闭包保存一个变量而不是状态的实际解决方法
//怎么才能不写辣么多prototype
function Fes(){
}
Fes.prototype={
constructor: Fes,
name:"圣诞节",
say:function(){
console.log("圣诞节快乐");
}
}
var fes = new Fes();
console.log(fes.constructor == Fes);
console.log(Fes.prototype.constructor == Fes);
```
//组合使用函数和原型链,又可以传参,还有公用方法
function Fest (name){
this.name = name;
}
Fest.prototype.say = function(){
console.log(this.name+"快乐");
}
var fest = new Fest("圣诞节");
fest.say();
//寄生构造模式,new+构造函数
//如果不return,则返回实例
//return可以重写构造函数返回的值
function Festi(name){
var o = new Object();
o.name = name;
o.say = function(){
console.log(this.name+"快乐");
}
return o;
}
var festi = new Festi("圣诞节");
festi.say();
//继承之原型链
function Super(){
this.name = "节日";
this.say = function(){
console.log("这里的this是什么?");
console.log(this.name+"快乐");
console.log("节日快乐");
}
}
function Sub(name){
this.name = name;
this.sayMe = function(){
console.log(this.name+"快乐");
}
}
//错误的写法
//sub.prototype = super;
Sub.prototype = new Super();
var apple = new Sub("圣诞节");
apple.say();
apple.sayMe();