js继承封装（三）-蒲公英云

js继承封装（三）

Myth丶恋晨 2022-08-10 06:16 213阅读 0赞

封装继承方法

//实现继承 subClass为子类 superClass为父类
function extendsClass(subClass,superClass){ 
    var oldPrototype=subClass.prototype;
    var Clazz=new Function();
    Clazz.prototype=superClass.prototype;
    subClass.prototype=new Clazz();
    subClass.prototype.constructor=subClass;
    for(var key in oldPrototype){
        if(oldPrototype.hasOwnProperty(key)){
            subClass.prototype[key]=oldPrototype[key];
        }
    }
}
function UpdateCommand(path) { 
    this.name="修改命令";
    this.path = path;
    this.executeFun=function(){ 
        alert("发送请求1");
    }
}
UpdateCommand.prototype.execute = function () { 
    alert("发送请求2");
}
//定义一个查询command函数
function QueryCommand(path) { 
    UpdateCommand.call(this,path);
}
QueryCommand.prototype.execute=function(){ 
    alert("发送查询请求");
}
extendsClass(QueryCommand,UpdateCommand);
var queryCommand = new QueryCommand();
queryCommand.execute();
//发送查询请求

对封装方法简单的说明下

//实现继承 subClass为子类 superClass为父类
function extendsClass(subClass,superClass){ 
    //临时存放 用于后面使用
    var oldPrototype=subClass.prototype;
    //生成新函数，通过该函数来实现原型继承，则减少了superClass的实例化
    var Clazz=new Function();
    clazz.prototype=superClass.prototype;
    subClass.prototype=new Clazz();
    //改变原型继承后子类的constructor 指向
    subClass.prototype.constructor=subClass;
    //保证子类方法重载
    for(var key in oldPrototype){
        if(oldPrototype.hasOwnProperty(key)){
            subClass.prototype[key]=oldPrototype[key];
        }
    }
}