According to this Jayway JsonPath evaluator, you could use this JsonPath to return a list of the values you are going for (careful… the json you posted is not in code fences, so it has smart quotes in it)…
$[*][*][0]
Or, if you wanted to get a specific value…
$..[?(@.FraksjonId==7)].Tommedatoer[0]
The functionality of the JSONPATH transformation service has unfortunately been reduced to only allow JSONPATH results that return strings and single element lists. A JSONPATH that returns multiple elements is not supported by the transform. In this case, you would get an error, null or the entire original json, I’m not sure which.
There are other options for this, such as using a JS transform, or pulling the raw data into an item and then calculating the value in a rule using executeCommandLine with jq and updating items. Untested…
import java.util.List
...
// somewhere in your rule
val List<String> trashTimeList = executeCommandLine("/bin/sh@@-c@@/usr/bin/echo " + Raw_Date.state.toString + " | /usr/bin/jq '.[].Tommedatoer[0]'",10000).split("\n")