missing "key" when it's the last item

[MrRoooo]

When the item's price is blank and the last one, it will not be included it in the json. Hope I explained it correctly.

The first item does not have the price for Walmart and the json is missing Walmart for the first item.
The 5th item, does not have the price for Publix, but the json has a blank price for Publix.