Single JSON document from a list of custom data types held in an app state.

Any ideas here?

I have a custom data type (update) that are held in a list in a persisted app state (updateTable). Instead of making multiple API calls on each individual item to post it to Xano, I'd like to produce a single JSON document of all the items within the list and then post it. I've already set up Xano to process through it. My struggle is producing the single JSON document within Flutterflow to submit it to the API.