export declare enum Operator {
    $PROJECT = "$project",
    $MATCH = "$match",
    $LOOKUP = "$lookup",
    $SKIP = "$skip",
    $LIMIT = "$limit",
    $SORT = "$sort",
    $GROUP = "$group",
    $ADDFIELDS = "$addFields",
    $UNWIND = "$unwind",
    $COUNT = "$count",
    $EXISTS = "$exists",
    $AND = "$and",
    $OR = "$or",
    $BETWEEN = "$between",
    $NIN = "$nin",
    $IN = "$in"
}