https://docs.mongodb.com/manual/reference/operator/aggregation/#array-expression-operators
This ticket tracks the addition of $last, $map, $objectToArray, $range, $reduce, $reverseArray, $size, and $zip to the CST.
Note that $slice has already been implemented.
The addition of the other agg array operators is tracked by: https://jira.mongodb.org/browse/SERVER-48863