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         


        

Answer 1

You will need to replace

{category:rating}

with

var obj = {};
obj[category] = rating;

Answer 2

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;

Answer 3

When creating an object literal the key must be a string, so in your code it will be "category". If instead you do:

  var rating="1"
  var category="somecat";
  var user="user1";

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

   cart[user][category]=rating;

That will initialise a non existing user to an empty object and then add the category.