内部对象。Create是这样做的:

Object.create = function (o) {
    function F() {}
    F.prototype = o;
    return new F();
};

语法只是消除了JavaScript使用经典继承的错觉。

function Test(){
    this.prop1 = 'prop1';
    this.prop2 = 'prop2';
    this.func1 = function(){
        return this.prop1 + this.prop2;
    }
};

Test.prototype.protoProp1 = 'protoProp1';
Test.prototype.protoProp2 = 'protoProp2';
var newKeywordTest = new Test();
var objectCreateTest = Object.create(Test.prototype);

/* Object.create   */
console.log(objectCreateTest.prop1); // undefined
console.log(objectCreateTest.protoProp1); // protoProp1 
console.log(objectCreateTest.__proto__.protoProp1); // protoProp1

/* new    */
console.log(newKeywordTest.prop1); // prop1
console.log(newKeywordTest.__proto__.protoProp1); // protoProp1

简介:

1)用new关键字有两点要注意;

A)函数被用作构造函数

b)函数。原型对象被传递给__proto__属性…或者在不支持__proto__的地方，它是新对象寻找属性的第二个地方

2)使用object .create(obj.prototype)你正在构造一个对象(obj.prototype)并将其传递给预期的对象。不同的是，现在new object的__proto__也指向obj。原型(请参考ans by xj9)

区别在于所谓的“伪经典vs.原型继承”。建议在代码中只使用一种类型，不要混合使用两种类型。

在伪经典继承中(使用"new"操作符)，假设您首先定义了一个伪类，然后从该类创建对象。例如，定义一个伪类“Person”，然后从“Person”创建“Alice”和“Bob”。

在原型继承中(使用Object.create)，您直接创建一个特定的人“Alice”，然后使用“Alice”作为原型创建另一个人“Bob”。这里没有“阶级”;都是对象。

在内部，JavaScript使用“原型继承”;“伪古典”的方式只是一些糖。

查看这两种方法的比较。

对象创建变量。

变体1:'new Object()' ->不带参数的对象构造函数。

var p1 = new Object(); // 'new Object()' create and return empty object -> {}

var p2 = new Object(); // 'new Object()' create and return empty object -> {}

console.log(p1); // empty object -> {}

console.log(p2); // empty object -> {}

// p1 and p2 are pointers to different objects
console.log(p1 === p2); // false

console.log(p1.prototype); // undefined

// empty object which is in fact Object.prototype
console.log(p1.__proto__); // {}

// empty object to which p1.__proto__ points
console.log(Object.prototype); // {}

console.log(p1.__proto__ === Object.prototype); // true

// null, which is in fact Object.prototype.__proto__
console.log(p1.__proto__.__proto__); // null

console.log(Object.prototype.__proto__); // null

变量2:'new Object(person)' ->带参数的对象构造函数。

const person = {
    name: 'no name',
    lastName: 'no lastName',
    age: -1
}

// 'new Object(person)' return 'person', which is pointer to the object ->
//  -> { name: 'no name', lastName: 'no lastName', age: -1 }
var p1 = new Object(person);

// 'new Object(person)' return 'person', which is pointer to the object ->
//  -> { name: 'no name', lastName: 'no lastName', age: -1 }
var p2 = new Object(person);

// person, p1 and p2 are pointers to the same object
console.log(p1 === p2); // true
console.log(p1 === person); // true
console.log(p2 === person); // true

p1.name = 'John'; // change 'name' by 'p1'
p2.lastName = 'Doe'; // change 'lastName' by 'p2'
person.age = 25; // change 'age' by 'person'

// when print 'p1', 'p2' and 'person', it's the same result,
// because the object they points is the same
console.log(p1); // { name: 'John', lastName: 'Doe', age: 25 }
console.log(p2); // { name: 'John', lastName: 'Doe', age: 25 }
console.log(person); // { name: 'John', lastName: 'Doe', age: 25 }

变体3.1:'Object.create(person)'。使用对象。用简单的对象“person”创建。' object. create(person)'将创建(并返回)新的空对象，并将属性'__proto__'添加到相同的新空对象。属性'__proto__'将指向对象'person'。

const person = {
        name: 'no name',
        lastName: 'no lastName',
        age: -1,
        getInfo: function getName() {
           return `${this.name} ${this.lastName}, ${this.age}!`;
    }
}

var p1 = Object.create(person);

var p2 = Object.create(person);

// 'p1.__proto__' and 'p2.__proto__' points to
// the same object -> 'person'
// { name: 'no name', lastName: 'no lastName', age: -1, getInfo: [Function: getName] }
console.log(p1.__proto__);
console.log(p2.__proto__);
console.log(p1.__proto__ === p2.__proto__); // true

console.log(person.__proto__); // {}(which is the Object.prototype)

// 'person', 'p1' and 'p2' are different
console.log(p1 === person); // false
console.log(p1 === p2); // false
console.log(p2 === person); // false

// { name: 'no name', lastName: 'no lastName', age: -1, getInfo: [Function: getName] }
console.log(person);

console.log(p1); // empty object - {}

console.log(p2); // empty object - {}

// add properties to object 'p1'
// (properties with the same names like in object 'person')
p1.name = 'John';
p1.lastName = 'Doe';
p1.age = 25;

// add properties to object 'p2'
// (properties with the same names like in object 'person')
p2.name = 'Tom';
p2.lastName = 'Harrison';
p2.age = 38;

// { name: 'no name', lastName: 'no lastName', age: -1, getInfo: [Function: getName] }
console.log(person);

// { name: 'John', lastName: 'Doe', age: 25 }
console.log(p1);

// { name: 'Tom', lastName: 'Harrison', age: 38 }
console.log(p2);

// use by '__proto__'(link from 'p1' to 'person'),
// person's function 'getInfo'
console.log(p1.getInfo()); // John Doe, 25!

// use by '__proto__'(link from 'p2' to 'person'),
// person's function 'getInfo'
console.log(p2.getInfo()); // Tom Harrison, 38!

变体3.2:'Object.create(Object.prototype)'。使用对象。创建内置对象-> ' object .prototype'。' object. create(object. prototype)'将创建(并返回)新的空对象，并将属性'__proto__'添加到相同的新空对象。属性'__proto__'将指向对象' object .prototype'。

// 'Object.create(Object.prototype)' :
// 1. create and return empty object -> {}.
// 2. add to 'p1' property '__proto__', which is link to 'Object.prototype'
var p1 = Object.create(Object.prototype);

// 'Object.create(Object.prototype)' :
// 1. create and return empty object -> {}.
// 2. add to 'p2' property '__proto__', which is link to 'Object.prototype'
var p2 = Object.create(Object.prototype);

console.log(p1); // {}

console.log(p2); // {}

console.log(p1 === p2); // false

console.log(p1.prototype); // undefined

console.log(p2.prototype); // undefined

console.log(p1.__proto__ === Object.prototype); // true

console.log(p2.__proto__ === Object.prototype); // true

变体4:'new SomeFunction()'

// 'this' in constructor-function 'Person'
// represents a new instace,
// that will be created by 'new Person(...)'
// and returned implicitly
function Person(name, lastName, age) {

    this.name = name;
    this.lastName = lastName;
    this.age = age;

    //-----------------------------------------------------------------
    // !--- only for demonstration ---
    // if add function 'getInfo' into
    // constructor-function 'Person',
    // then all instances will have a copy of the function 'getInfo'!
    //
    // this.getInfo: function getInfo() {
    //  return this.name + " " + this.lastName + ", " + this.age + "!";
    // }
    //-----------------------------------------------------------------
}

// 'Person.prototype' is an empty object
// (before add function 'getInfo')
console.log(Person.prototype); // Person {}

// With 'getInfo' added to 'Person.prototype',
// instances by their properties '__proto__',
// will have access to the function 'getInfo'.
// With this approach, instances not need
// a copy of the function 'getInfo' for every instance.
Person.prototype.getInfo = function getInfo() {
    return this.name + " " + this.lastName + ", " + this.age + "!";
}

// after function 'getInfo' is added to 'Person.prototype'
console.log(Person.prototype); // Person { getInfo: [Function: getInfo] }

// create instance 'p1'
var p1 = new Person('John', 'Doe', 25);

// create instance 'p2'
var p2 = new Person('Tom', 'Harrison', 38);

// Person { name: 'John', lastName: 'Doe', age: 25 }
console.log(p1);

// Person { name: 'Tom', lastName: 'Harrison', age: 38 }
console.log(p2);

// 'p1.__proto__' points to 'Person.prototype'
console.log(p1.__proto__); // Person { getInfo: [Function: getInfo] }

// 'p2.__proto__' points to 'Person.prototype'
console.log(p2.__proto__); // Person { getInfo: [Function: getInfo] }

console.log(p1.__proto__ === p2.__proto__); // true

// 'p1' and 'p2' points to different objects(instaces of 'Person')
console.log(p1 === p2); // false

// 'p1' by its property '__proto__' reaches 'Person.prototype.getInfo' 
// and use 'getInfo' with 'p1'-instance's data
console.log(p1.getInfo()); // John Doe, 25!

// 'p2' by its property '__proto__' reaches 'Person.prototype.getInfo' 
// and use 'getInfo' with 'p2'-instance's data
console.log(p2.getInfo()); // Tom Harrison, 38!

object中使用的对象。create实际上形成了新对象的原型，而在new Function()形式中，声明的属性/函数不形成原型。

是的,对象。Create构建一个直接继承作为其第一个参数传递的对象的对象。

使用构造函数，新创建的对象继承自构造函数的原型，例如:

var o = new SomeConstructor();

在上面的例子中，o直接继承自SomeConstructor.prototype。

这里有一个不同，对象。你可以创建一个不继承任何东西的对象object .create(null);，另一方面，如果你设置SomeConstructor。原型= null;新创建的对象将继承object .prototype。

你不能用对象创建闭包。像使用函数式语法一样创建语法。考虑到JavaScript的词法(相对于块)类型范围，这是合乎逻辑的。

你可以创建闭包，例如使用属性描述符参数:

var o = Object.create({inherited: 1}, {
  foo: {
    get: (function () { // a closure
      var closured = 'foo';
      return function () {
        return closured+'bar';
      };
    })()
  }
});

o.foo; // "foobar"

注意，我说的是ECMAScript第5版对象。create方法，而不是Crockford's shim。

该方法已开始在最新的浏览器上本机实现，请检查此兼容性表。

让我试着解释(更多在博客上):

When you write Car constructor var Car = function(){}, this is how things are internally: We have one {prototype} hidden link to Function.prototype which is not accessible and one prototype link to Car.prototype which is accessible and has an actual constructor of Car. Both Function.prototype and Car.prototype have hidden links to Object.prototype. When we want to create two equivalent objects by using the new operator and create method then we have to do it like this: Honda = new Car(); and Maruti = Object.create(Car.prototype). What is happening? Honda = new Car(); — When you create an object like this then hidden {prototype} property is pointed to Car.prototype. So here, the {prototype} of the Honda object will always be Car.prototype — we don't have any option to change the {prototype} property of the object. What if I want to change the prototype of our newly created object? Maruti = Object.create(Car.prototype) — When you create an object like this you have an extra option to choose your object's {prototype} property. If you want Car.prototype as the {prototype} then pass it as a parameter in the function. If you don't want any {prototype} for your object then you can pass null like this: Maruti = Object.create(null).

结论-通过使用方法对象。创建时你可以自由选择你的对象{prototype}属性。在new Car();中，你没有这样的自由。

面向对象JavaScript的首选方式:

假设我们有两个对象a和b。

var a = new Object();
var b = new Object();

现在，假设a有一些b也想访问的方法。为此，我们需要对象继承(只有当我们想要访问这些方法时，a才应该是b的原型)。如果我们检查a和b的原型，我们会发现它们共享Object.prototype原型。

Object.prototype.isPrototypeOf(b); //true
a.isPrototypeOf(b); //false (the problem comes into the picture here).

问题-我们想要对象a作为b的原型，但是在这里我们用原型object .prototype创建了对象b。 解决方案- ECMAScript 5引入了Object.create()，可以轻松实现这种继承。如果我们像这样创建对象b:

var b = Object.create(a);

然后,

a.isPrototypeOf(b);// true (problem solved, you included object a in the prototype chain of object b.)

因此，如果你正在编写面向对象的脚本，那么object .create()对于继承非常有用。