3
看看下面的例子,其中来自Person
Student
继承:在继承Javascript中的对象时需要“Subclass.prototype.constructor = Subclass”吗?
function Person(name) {
this.name = name;
}
Person.prototype.say = function() {
console.log("I'm " + this.name);
};
function Student(name, id) {
Person.call(this, name);
this.id = id;
}
Student.prototype = new Person();
// Student.prototype.constructor = Student; // Is this line really needed?
Student.prototype.say = function() {
console.log(this.name + "'s id is " + this.id);
};
console.log(Student.prototype.constructor); // => Person(name)
var s = new Student("Misha", 32);
s.say(); // => Misha's id is 32
正如你所看到的,实例化一个对象Student
并调用其方法工作得很好,但Student.prototype.constructor
回报Person(name)
,这似乎是我错了。
如果我添加:
Student.prototype.constructor = Student;
然后Student.prototype.constructor
回报Student(name, id)
,符合市场预期。
我应该总加Student.prototype.constructor = Student
吗?
你可以举个例子吗?
的可能重复[什么是JavaScript构造属性的意义是什么?(http://stackoverflow.com/questions/4012998/what-it-the-significance-of-the-javascript-constructor-属性) – Domenic