MongoDB remove all matching items from sub-sub-array - mongodb

Question

Just wondering what the best way to accomplish this is. I can think of some janky ways, but they don't seem right.
What I'm trying to do is remove all sub-sub-array objects from a documents. Like follows:
SCHEMA
schema {
person: Array<{
id: string;
posts: Array<{
id: string,
comments: Array<{
id: string
tagged_person_id: string;
}>
}>
}>
}
What I am looking for some way to delete all comments in every post for each person where the comment has tagged_person_id == some_id. This isn't my actually use-case, but it represents the same concept.
I know how to use $pull to remove from a subarray for one subdocument, but just not sure how to accomplish all of this in one query, or if it's even possible.

Answer 1

As per JIRA ticket SERVER-1243 and the documentation, starting with MongoDB v3.5.12, given the following document:
{
"posts" : [
{
"comments" : [
{
"tagged_person_id" : "x"
},
{
"tagged_person_id" : "y"
}
]
},
{
"comments" : [
{
"tagged_person_id" : "x"
}
]
},
{
"comments" : [
{
"tagged_person_id" : "y"
}
]
}
]
}
You can run this update:
db.collection.update({}, {
$pull : {
"posts.$[].comments" : {"tagged_person_id": "x"}
}
})
in order to remove all comments where tagged_person_id is equal to "x".
Result:
{
"posts" : [
{
"comments" : [
{
"tagged_person_id" : "y"
}
]
},
{
"comments" : []
},
{
"comments" : [
{
"tagged_person_id" : "y"
}
]
}
]
}