Object.create()

function Test(){
    this.myString = 'Hello'
}

var a = new Test();
console.log(a.myString); //Hello

var b = Object.create(Test);
console.log(b.myString);//undefined

var c = Object.create(a);
console.log(c.myString);//Hello

Do not confuse Object.create() with new. Object.create(proto) creates a new object using the proto as the prototype object.

The example above shows how var b has not got the myString property because when calling the Object.create() we gave it a constructor rather then an object to set as the prototype.

However var c has the property myString because we gave the Object.create an object to be used as the prototype. So when we reference myString it can traverse up the prototype tree.

Below is an example showing how to achieve the same effect with out the use of Object.create() and using new.


//set up my object to inherit from
function Testprototype(){
  this.myString = 'aTest';
}
var a = new Testprototype();

//create object with a as prototype
var b = Object.create(a);


//equivalent as above with new
function Empty(){
//dummy constructor
}
Empty.prototype = a;
var c = new Empty();

//results
console.log(b);// Testprototype { myString="aTest"}
console.log(c);// Testprototype { myString="aTest"}

MDN Object.create()