js繼承摘要

對象的構造函數是指向建立對象的類的原型對象的構造函數。

類是一個Function, Function都有原型對象,原型對象的構造函數指向類的聲明。

function Person(){

}

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

var p1 = new Person();

p1.constructor === Person  //true

 

a.prototype = {}  等價於 a.prototype = new object({});

此時 a.prototype.constructor 指向錯誤， 指到了object上

應該修正： a.prototype.constructor = a

原型繼承typescript代碼：

 

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;
    }
}

 

對應的js代碼：

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));