js继承摘要

对象的构造函数是指向创建对象的类的原型对象的构造函数。

类是一个Function, Function都有原型对象,原型对象的构造函数指向类的声明。

function Person(){

}

Person.prototype.constructor === Person //true

var p1 = new Person();

p1.constructor === Person  //true

a.prototype = {}  等价于 a.prototype = new object({});

此时 a.prototype.constructor 指向错误， 指到了object上

应该修正： a.prototype.constructor = a

原型继承typescript代码：

class Person {
    constructor(private name: string) {

    }

    getName() {
        return this.name;
    }
}

class Employee extends Person {
    constructor(name: string, private age: number) {
        super(name);
    }

    getAge() {
        return this.age;
    }
}

对应的js代码：

var __extends = (this && this.__extends) || function (d, b) {
    for (var p in b)
        if (b.hasOwnProperty(p))
            d[p] = b[p];
    function __() { this.constructor = d; }
    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var Person = (function () {
    function Person(name) {
        this.name = name;
    }
    Person.prototype.getName = function () {
        return this.name;
    };
    return Person;
}());
var Employee = (function (_super) {
    __extends(Employee, _super);
    function Employee(name, age) {
        _super.call(this, name);
        this.age = age;
    }
    Employee.prototype.getAge = function () {
        return this.age;
    };
    return Employee;
}(Person));