Update a Firebase List in HTTP REQUEST

I’m working with LISTS and wanted to know how I do to repeat the list by HTTP patch

“List”: { “arrayValue”: { “values”: [ { “stringValue”: “string1” }

How do I copy the current list via formula and add one more item?

exemple :
“List”: { “arrayValue”: { “values”: [ { data.list.atual } + new item

You can add an item to a list with - WITH_ITEM(List, NewItem)