这是一个来自学习阶段新手的相当普遍的问题，是我需要澄清的问题。

我目前正在学习对象，此时我正在学习继承。在本课的这一点上，我已经学习了几种不同的创建对象的方法，但使用 this 来创建对象。关键字似乎具有最多的功能:

function Person(){
    this.eyes = 2;
    this.ears = 2;
    this.arms = 2;
    this.hands = 2;
    this.feet = 2;
    this.legs = 2;
    this.species = "Homo sapien";
    }

var person = new Object();
person.eyes = 2;
person.ears = 2;
person.arms = 2;
person.hands = 2;
person.feet = 2;
person.legs = 2;
person.species = "Homo sapien";

最佳答案

前言 :如果您不确定我下面的“原型(prototype)”一词是什么意思，请跳到分隔符下方进行解释，然后再回到答案的顶部。 :-)

假设在您的第一个示例中，您然后调用 Person通过 new :

var person = new Person();

I'm wondering if there's any reason why I wouldn't just use the former method all the time

var person = {
    eyes: 2,
    ears: 2,
    arms: 2,
    hands: 2,
    feet: 2,
    legs: 2,
    species: "Homo sapien"
};

function buildPerson() {
    return {
        eyes: 2,
        ears: 2,
        arms: 2,
        hands: 2,
        feet: 2,
        legs: 2,
        species: "Homo sapien"
    };
}
var person = buildPerson();

var personPrototype = {
    // ...properties for the person prototype...
};
function buildPerson() {
    var obj = Object.create(personPrototype);
    obj.eyes = 2;
    obj.ears = 2;
    obj.arms = 2;
    obj.hands = 2;
    obj.feet = 2;
    obj.legs = 2;
    obj.species = "Homo sapien";
    return obj;
}
var person = buildPerson();

var proto = {
    name: "proto's name"
};
var obj = Object.create(proto); // Creates an object backed by the given prototype

console.log(obj.name);

var proto = {
    name: "proto's name"
};
var obj = Object.create(proto); // `obj` is backed by `proto`
console.log(obj.name);          // "proto's name"
obj.name = "obj's name";
console.log(obj.name);          // "obj's name"

var proto = {
    name: "proto's name"
};
var a = Object.create(proto);   // `a` is backed by `proto`
var b = Object.create(proto);   // `b` is also backed by `proto`
console.log(a.name);            // "proto's name"
console.log(b.name);            // "proto's name"
a.name = "a's name";
console.log(a.name);            // "a's name"
console.log(b.name);            // "proto's name"

var proto = {
    name: "proto's name"
};
var obj = Object.create(proto);
console.log(obj.name);          // "proto's name"
proto.name = "updated";
console.log(obj.name);          // "updated"

function Person(name) {
    this.name = name;
}
Person.prototype.sayName = function() {
    console.log("My name is " + this.name);
};
var p = new Person("Fred"); // Creates an object backed by Person.prototype,
                            // then calls Person with this referring to the
                            // object
p.sayName();                // "My name is Fred";

var rootProto = {
    name: "root proto's name"
};
var middleProto = Object.create(rootProto);
middleProto.middleProp = "middle property";
var obj = Object.create(middleProto);
console.log(obj.name);       // "root proto's name"
console.log(obj.middleProp); // "middle property"

var proto = {/*...*/};
var obj = Object.create(proto);
Object.getPrototypeOf(obj) === proto; // true

关于javascript - Javascript 中的对象类型，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32076090/