There seems to be no way to pass a multi-line param?
Correct. But there might a workaround with apoc.
Drop a JSON file somewhere, and use apoc.load.json with a file:
path prefix.
Example
C:/path/myjson.json
{
"testlist": [
"test",
"list"
]
}
Cypher Command
CALL apoc.load.json("file:/C:/path/myjson.json") YIELD value
WITH value.testlist AS testlist
...
It's not as nice as a param, and doesn't come with the performance advantages, but at least you can have well-structured data.