Javascript对象继承与函数继承

鉴别一个原型属性

function hasPrototypeProperty(object, name) {
    return name in object && !object.hasOwnProperty(name);
}

在构造函数中使用原型对象

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

Person.prototype = {
    constructor: Person,
    sayName: function () {
       console.log(this.name);
    },
    toString: function() {

    }
};

var person1 = new Person('Nicholas');
var person2 = new Person('Greg);

console.log(person1 instanceof Person); // true
console.log(person1.constructor === Person); // true
console.log(person1.constructor === Object); // false

console.log(person2 instanceof Person); // true
console.log(person2.constructor === Person); // true
console.log(person2.constructor === Object); // false

对象继承

var person1 = {
    name: 'Nicholas',
    sayName: function () {
        console.log(this.name);
    }
};

var person2 = Object.create(person1, {
    name: {
        configurable: true,
        enumerable: true,
        value: 'Greg',
        writable: true
    }
});

person1.sayName(); // Nicholas
person2.sayName(); // Greg

console.log(person1.hasOwnProperty('sayName')); // true
console.log(person1.isPropertyOf(person2)); // true
console.log(person2.hasOwnProperty('sayName')); // false

模块模式

var person = (function () {
    var age = 25;

    function getAge() {
        return age;
    }

    function growOlder() {
        age++;
    }

    return {
        name: 'Nicholas',
        getAge: getAge,
        growOlder: growOlder
    };
}());

作用域的构造函数

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

Person.prototype.sayName = function() {
    console.log(this.name);
};

var person1 = Person('Nicholas');

console.log(person1 instanceof Person); // false
console.log(typeof person1); // undefined
console.log(name); // Nicholas