extend array objects with jquery

gistfile1.js

  copy = {
    bundle_offers : [
      {
        title : 'teste1'
      },
      {
        title : 'teste2'
      }
    ]
  }
  
  copy.bundle_offers[ 0 ] = $.extend({}, copy.bundle_offers[ 0 ], {
    description : 'description'
  });
  
  console.log( copy.bundle_offers );