Find and FindIndex for Array operations in Sub-document API

For Couchbase subdocument operations, we can use arrayAppend and arrayPrepend which allows to edit in place an array of values without retrieving the full document or the full array.
However in node JS arrays [] it is required to know the index to operate on for an UPDATE or DELETE operation.
So in effect it does not seem possible, at least with the nodeJS SDK, to edit an array of values without retrieving the whole array, to find the Index of the item to be edited.
It would be useful if couchbase would provide methods such as “find” or “findIndex” that are available natively on JS arrays. We should be able to do:

            .findIndex( item => === itemId)
            .execute((err, res) => {
                 // get index of item to remove or update without fetching the full array

and then:

// remove specific item in array
                    .execute((err, res) => {})

Or maybe add “find” method in “mutateIn” to do everything in one go. Would be nice to also add a “map” method and other JS Array methods like “reduce”.