QueryOrderByConstraint
A QueryOrderByConstraint is used to sort the set of documents returned by a
Firestore query. QueryOrderByConstraints are created by invoking
orderBy and can then be passed to {@link (query:1)} to create a new query
instance that also contains this QueryOrderByConstraint.
Note: Documents that do not contain the orderBy field will not be present in the query result.
class QueryOrderByConstraint extends QueryConstraint {}
readonly type: string;