Show all records if URL param is empty?

Hi Everyone

I'm doing a fetch GET request to my API endpoint.

I have an external filter setup for members location, which is sent to the API as a URL param.
'URL_ENDPOINT?location=27' and this works. Shows results for location 27.

I have set this up following the Xano docs on External Filtering. My input 'location' is of type integer (the id from the locations table).

But how can I return all locations if a user selects nothing in the frontend?
This should be the default value too on page load.

I've tried null or nothing and they don't work.

'?location=null' = ('Value 'null ' is not a valid integer.')
'?location=' [] (empty array)

TIA
~James