JS__class 入坑 chrome测试class 父子类 继承关系

class A{ ???constructor(){//并非必须 ???????this.name="class_A"; ???????//console.log(this) //A {name: "class_A"} (另起一行)B {name: "class_A"} //父类子类分别执行了一次 ???} ???static staticCallNameA(){ ???return "name_A"; ???} ???callNameA(){ ???return "name_A"; ???} ???static cover(){ ???return "cover_A" ???}}class B extends A{ ???constructor(){//子类可以不加 ???super();//子类必须有 ???//console.log(this)//B {name: "class_A"} //会直接打印 ???} ???static staticCallNameB(){ ???return "nameB"; ???} ???callNameB(){ ???return "name_B"; ???} ???static cover(){ ???return "cover_B" ???}}

console.log(A.name,B.name) //A B //(类名)console.log(A.staticCallNameA(),B.staticCallNameA()) //static子类继承父类console.log(A.cover(),B.cover()) //cover_A cover_B //先读子类再读父类console.log(A.staticCallNameB) //undefined //父类不具备子类特有函数console.log(A.callNameA,B.callNameA) //undefined undefined //非static方法类不能直接调用let a=new A(),b=new B; //加不加括号效果一样console.log(a.name); //class_Aconsole.log(a.name,b.name) //class_A class_Aconsole.log(a.callNameA(),a.callNameB,b.callNameB(),b.callNameA()) //name_A undefined name_B name_A //说明继承关系同上