JavaScript继承的实现

Posted 2020-09-27 cxchanpin

javascript继承有构造函数继承、原型继承、复制继承、构造函数/原型组合继承等方法，这些继承方法各有特点。眼下最经常使用的就是构造函数/原型组合继承。

/**
 * 实现继承
 * @param  subType    {Function}  子类构造函数
 * @param  superType  {Function}  父类构造函数
 */
function inherit(subType, superType){
    function F(){}
    F.prototype = superType.prototype;

    var p = new F();
    p.constructor = subType;
    subType.prototype = p;
}

/**
 * 父类
 * @param  name  {String}  姓名
 * @param  age   {Number}  年龄
 */
function Person(name, age){
    this.name = name;
    this.age = age;
}

Person.prototype.getName = function(){
    return this.name;
};

Person.prototype.setName = function(name){
    this.name = name;
};

Person.prototype.getAge = function(){
    return this.age;
};

Person.prototype.setAge = function(age){
    this.age = age;
};


/**
 * 子类
 * @param  name       {String}  姓名
 * @param  age        {Number}  年龄
 * @param  education  {String}  教育程度
 */
function Student(name, age, education){
    this.education = education;

    //调用父类构造函数
    Person.call(this, name, age);
}

//实现继承
//一定要在声明子类原型方法之前，否则会被覆盖。

inherit(Student, Person);

Student.prototype.setEducation = function(education){
    this.education = education;
};

Student.prototype.getEducation = function(){
    return this.education;
};

var person = new Person(‘小明‘, 25);
var student = new Student(‘小刚‘, 22, ‘本科‘);

person instanceof Person; //true
student instanceof Person; //true
student instanceof Student; //true

父类属性及方法

子类属性及方法