了解原型继承

Question

var Object1 = {};
var Object2 = new Object();
var Object3 = Object.create({});

When i check whether the prototype is equal to Object.prototype :

The first two return true while the third one returns false .

Why is this happening?

Object.getPrototypeOf(Object1)===Object.prototype //true
Object.getPrototypeOf(Object2)===Object.prototype //true
Object.getPrototypeOf(Object3)===Object.prototype //false

Answer 1

Simply because if you take a look at the Object.create() in the documentation, you will that this method:

creates a new object with the specified prototype object and properties.

And if you call it with :

Object.create({})

You are not passing a prototype but an empty object with no properties.

So as stated in comments you need to call it like this:

Object.create(Object.prototype)

Answer 2

The Object.create() method creates a new object with the specified prototype object and properties.

Behind the scenes it does the following:

Object.create = (function() {
  var Temp = function() {};
  return function (prototype) {
    if (arguments.length > 1) {
      throw Error('Second argument not supported');
    }
    if (typeof prototype != 'object') {
      throw TypeError('Argument must be an object');
    }
    Temp.prototype = prototype;
    var result = new Temp();
    Temp.prototype = null;
    return result;
  };
})();

So the right use would be:

var Object3 = Object.create(Object.prototype);

Or if you want to make your example work:

Object.getPrototypeOf(Object.getPrototypeOf(Object3)) === Object.prototype // true 

Here the prototype chain comes into play:

console.dir(Object3)
 -> __proto__: Object (=== Your Object Literal)
   -> __proto__: Object (=== Object.prototype)