DocumentFromStruct creates a bson document from a struct in the order of the underlying data structure.

FlattenDocument consumes a struct or map and returns a flattened BSON document (bson.D) where embedded structs and maps are flattened into the root level of the map and field-names are concatenated by dots ('.').

MarshallBSONOrDocumentFromStruct marshals a structure to BSON if it implements the bson.Marshaler interface, otherwise invokes DocumentFromStruct on it.

UnwindMap takes a string map and perform mongodb $unwind aggregation operation on all array entries.

PermutationThreshold limits the complexity of Unwound maps to the given array length.

ErrPermutations is returned if the map contains arrays with a combined number of permutations than the threshold.