js继承函数封装

function extend(subClass,superClass) {
    //初始化一个中间空对象，为了转换主父类关系
    var F = function() {};
    F.prototype = superClass.prototype;
    //让子类继承F
    subClass.prototype = new F();
    subClass.prototype.constructor = subClass;
    //为子类增加属性superClass
    subClass.superClass = superClass.prototype;
    //增加保险，即使原型是超类Object，那句要把构造函数级别降下来
    if(superClass.prototype.constructor == Object.prototype.constructor) {
        superClass.prototype.constructor = superClass;
    }
}

function Author(name,book) {
    Author.superClass.constructor.call(this,name);
    this.book = book;
    this.getBook = function() {
        return this.name + '--' + this.book;
    }
}

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

extend(Author,Person);
var peter = new Author('long','keke');
console.log(peter.getBook())