Boxed.Mapping.md

Boxed.Mapping

A simple and fast (fastest?) object to object mapper that does not use reflection. Read A Simple and Fast Object Mapper for more information.

public class MapFrom
{
    public bool BooleanFrom { get; set; }
    public int IntegerFrom { get; set; }
    public List<MapFromChild> ChildrenFrom { get; set; }
}
public class MapFromChild
{
    public DateTimeOffset DateTimeOffsetFrom { get; set; }
    public string StringFrom { get; set; }
}
 
public class MapTo
{
    public bool BooleanTo { get; set; }
    public int IntegerTo { get; set; }
    public List<MapToChild> ChildrenTo { get; set; }
}
public class MapToChild
{
    public DateTimeOffset DateTimeOffsetTo { get; set; }
    public string StringTo { get; set; }
}

public class DemoMapper : IMapper<MapFrom, MapTo>
{
    private readonly IMapper<MapFromChild, MapToChild> childMapper;
    
    public DemoMapper(IMapper<MapFromChild, MapToChild> childMapper) => this.childMapper = childMapper;
    
    public void Map(MapFrom source, MapTo destination)
    {
        destination.BooleanTo = source.BooleanFrom;
        destination.IntegerTo = source.IntegerFrom;
        destination.ChildrenTo = childMapper.MapList(source.ChildrenFrom);
    }
}

public class DemoChildMapper : IMapper<MapFromChild, MapToChild>
{
    public void Map(MapFromChild source, MapToChild destination)
    {
        destination.DateTimeOffsetTo = source.DateTimeOffsetFrom;
        destination.StringTo = source.StringFrom;
    }
}

public class UsageExample
{
    private readonly IMapper<MapFrom, MapTo> mapper = new DemoMapper();
    
    public MapTo MapOneObject(MapFrom source) => this.mapper.Map(source);
    
    public MapTo[] MapArray(List<MapFrom> source) => this.mapper.MapArray(source);
    
    public List<MapTo> MapList(List<MapFrom> source) => this.mapper.MapList(source);
    
    public IAsyncEnumerable<MapTo> MapAsyncEnumerable(IAsyncEnumerable<MapFrom> source) =>
        this.mapper.MapEnumerableAsync(source);
}

Also includes IImmutableMapper<TSource, TDestination> which is for mapping to immutable types like C# 9 record's and can also be used for enum types.

public record MapFrom(bool BooleanFrom, int IntegerFrom);
public record MapTo(bool BooleanTo, int IntegerTo);

public class DemoImmutableMapper : IImmutableMapper<MapFrom, MapTo>
{
    public MapTo Map(MapFrom source) => 
        new MapTo(source.BooleanFrom, source.IntegerFrom);
}