jquery - Variable name getting added instead of its value, javascript

Question

I have a problem while adding values to a JavaScript object: the value to add is a key,value pair. Here is sample:

//JavaScript object

var cart=new Object();

function add()
{
  var rating="1"
  var category="somecat";
  var user="user1";

   if(cart[user]==null)

        cart[user]={category:rating};

   else

         cart[user][category]=rating;
 }

What I was expecting is that if user exists in cart object then value for his particular should get replaced, and if user doesn't exist then new user and category should be added.

The code is working fine when user already exists. Problem is, when I am adding a new element with cart[user]={category:rating} then its adding the variable name as key i.e. category , not the value inside it ("somecat").

Is there any way to do this using json, jquery or javascript itself?

Is there any way to assign value inside the variable?

Answer 1

There is no way to use a variable to define a property name inside object literal notation. It accepts identifiers or strings, but both identify property names, not variables.

You have to create the object then add the property:

if(!cart[user]) { 
   cart[user] = {};
}
cart[user][category] = rating;