Updating nested array n1ql - couchbase

Question

The sample doc, I am trying to work with is:
{
"name": "level1",
"childLevel1": [
{
"name": "level2",
"childLevel2": [
{
"name": "level3",
"childLevel3": [
{
"name": "level4",
"attribute1": "data"
}
]
}
]
}
]
}
What we want to do is, with n1ql add one more array element to "childLevel3". I have tried the reference to https://developer.couchbase.com/documentation/server/4.5/n1ql/n1ql-language-reference/update.html
I was able to add a regular attribute to childLevel2 but after that it was not working. This is the query I have been trying out.
Update sample
set child2.childLevel3 = ARRAY_PUT(child2.childLevel3, {'attribute' : 'data2'})
FOR child2 in child1.childLevel2 when child2.name == "level3" END
for child1 in childLevel1 when childLevel1.name == 'level2' END
WHERE name == 'level1'
But it gives me error on parsing, I tried other ways too but nothing works.

Answer 1

Try
UPDATE sample
SET child2.childLevel3 = ARRAY_PUT(child2.childLevel3, {'attribute' : 'data2'})
FOR child2 in child1.childLevel2
FOR child1 in childLevel1
WHEN childLevel1.name == 'level2' AND child2.name == "level3"
END
WHERE name == 'level1';

Answer 2

I had to update an object within a nested array, recently in Couchbase. The answer above helped me to formulate this query in a bucket called "metadata". The data structure is:
{
"documentMetadata": {
"documentId": "42"
},
"results": [
{
"type": "FileStaging",
"status": "NOT STARTED"
}
],
"type": "runLog"
}
The query that worked for me:
UPDATE metadata
SET res.status = 'QUEUED'
FOR res in results
WHEN res.type = 'FileStaging'
END
WHERE type = 'runLog'
AND documentMetadata.documentId = '42'