Shallow merge - MapsterMapper/Mapster GitHub Wiki
Deep copy vs shallow copy
By default, Mapster will recursively map nested objects (deep copy). You can do shallow copying by setting ShallowCopyForSameType to true.
TypeAdapterConfig<TSource, TDestination>
.NewConfig()
.ShallowCopyForSameType(true);
Copy vs Merge
By default, Mapster will map all properties, even source properties containing null values. You can copy only properties that have values (merge) by using IgnoreNullValues method.
TypeAdapterConfig<TSource, TDestination>
.NewConfig()
.IgnoreNullValues(true);