Why can I add named properties to an array as if it were an object?

Question

The following two different code snippets seem equivalent to me:

var myArray = Array();
myArray[\'A\'] = \"Athens\";
myArray[\'B\'] = \"Berlin\";
         


        

Answer 1

Everything in JavaScript is an object besides primitive types.

The code

var myArray = Array();

creates an instance of the Array object while

var myObject = {'A': 'Athens', 'B':'Berlin'};

creates an instance of Object object.

Try the following code

alert(myArray.constructor)
alert(myObject.constructor)

So you will see the difference is in the type of object constructor.

The instance of the Array object will contain all the properties and methods of the Array prototype.