jq 1.5 find nested elements by regex when parent unknown - regex

Question

Given the JSON structure below i would like to find the first occurrence of object ccc so I can add a new object to the children ddd. However I do not know the key name of the parent or how many levels deep it may be.
to find
"children": {
"ccc": [{
"id": "ddd",
"des": "object d",
"parent": "ccc"
}]
}
full JSON stored in $myJson
{
"zzz": [{
"id": "aaa",
"des": "object A",
"parent": "zzz",
"children": {
"aaa": [{
"id": "bbb",
"des": "object B",
"parent": "aaa",
"children": {
"bbb": [{
"id": "ccc",
"des": "object C",
"parent": "bbb",
"children": {
"ccc": [{
"id": "ddd",
"des": "object d",
"parent": "ccc"
}]
}
}, {
"id": "eee",
"des": "object e",
"parent": "bbb"
}]
}
},{
"id": "fff",
"des": "object f",
"parent": "aaa"
}]
}
}]}
follow some other answers I have tried combinations of
output=($(jq -r '.. | with_entries(select(.key|match("ccc";"i")))' <<< ${myjson}))
or
output=($(jq -r '.. | to_entries | map(select(.key | match("ccc";"i"))) | map(.value)' <<< ${myjson}))
all give errors of a similar nature jq: error (at <stdin>:1): number (0) cannot be matched, as it is not a string

Answer 1

In the following, I'll assume you want to add "ADDITIONAL" to the array at EVERY key that matches a given regex (here "ccc"):
walk(if type == "object"
then with_entries(if (.key|test("ccc"))
then .value += ["ADDITIONAL"] else . end)
else . end)
If your jq does not have walk/1, then you can simply copy-and-paste its def from the jq FAQ or builtin.jq
Alternative formulation
If you have the following general-purpose helper function handy (e.g. in your ~/.jq):
def when(filter; action): if (filter?) // null then action else . end;
then the above solution shrinks down to:
walk(when(type == "object";
with_entries(when(.key|test("ccc"); .value += ["ADDITIONAL"]))))