Node JS 中的原型继承

Question

来自经典继承背景（C#、Java 等），我正在努力使用原型方法来实现它。我也不了解基础知识。请在以下代码块中解释并纠正我。

    var util = require ('util'); 

function Student(choiceOfStream) { 
    this.choiceOfStream = choiceOfStream;
}

Student.prototype.showDetails = function() {
    console.log("A student of "+this.choiceOfStream+" has a major in "+this.MajorSubject);
}

function ScienceStudent() {
    Student.call(this,"Science");
}

function ArtsStudent() {
    Student.call(this,"Arts");
}

util.inherits(ScienceStudent,Student);
util.inherits(ArtsStudent,Student);

var ArtsStudent = new ArtsStudent(); 
var ScienceStudent = new ScienceStudent(); 

ScienceStudent.prototype.MajorSubject = "Math";
ArtsStudent.prototype.MajorSubject = "Literature";

console.log(ArtsStudent.showDetails());
console.log(ScienceStudent.showDetails());

但我得到的错误是

我错过了什么？

Answer 1

没有标准 this.super_ 属性所以我不确定你从哪里得到的。如果您正在使用 util.inherits()，您可以在 nodejs doc for util.inherits().

中看到一个很好的简单示例来说明如何使用它

而且，您的代码可以这样工作：

var util = require ('util');

function Student(choiceOfStream) { 
    this.choiceOfStream = choiceOfStream;
}

Student.prototype.showDetails = function() {
    console.log("A student of "+this.choiceOfStream+" has a major in "+this.MajorSubject);
}

function ScienceStudent() {
    Student.call(this, "Science");
    this.majorSubject = "Math";
}

function ArtsStudent() {
    Student(this,"Arts");
    this.majorSubject = "Literature";
}

util.inherits(ScienceStudent,Student);
util.inherits(ArtsStudent,Student);

仅供参考，在 ES6 语法中，有一个 super 关键字，它是声明 Javascript 继承（仍然是原型）的新方法的一部分，您可以阅读 here。

Node JS 中的原型继承

Prototypal Inheritence in Node JS

javascript

inheritance

prototypal-inheritance

node.js