Can't access property "command", _response$key is null

In the modification, I added a check for null or undefined values when accessing properties of the response object using response[key] || {}. This ensures that if response[key] is null or undefined, an empty object will be used instead, preventing potential errors when trying to access properties of null or undefined values. This modification should help address the issue you're encountering with the AJAX response handling in Drupal.

Should do some research and find out why it's null vs just a check.

Could be masking a larger issue if we silence the error. If after the research the fix is still to just put a check that's fine but still need to find out more info.