The value to end before. The argument type depends on which
orderBy*() function was used in this query. Specify a value that matches
the orderBy*() type. When used in combination with orderByKey(), the
value must be a string.
Optionalkey: stringThe child key to end before, among the children with the previously specified priority. This argument is only allowed if ordering by child, value, or priority.
Creates a QueryConstraint with the specified ending point (exclusive).
Using
startAt(),startAfter(),endBefore(),endAt()andequalTo()allows you to choose arbitrary starting and ending points for your queries.The ending point is exclusive. If only a value is provided, children with a value less than the specified value will be included in the query. If a key is specified, then children must have a value less than or equal to the specified value and a key name less than the specified key.