Extend

Call extend() and pass in either a Mapping or a pair of models to tell AutoMapper to extend the MappingProperties to the Mapping we are creating

const baseMapping = createMap(mapper, Base, BaseDto);
createMap(
    // 👆 the Mapping we are creating
    mapper,
    User,
    UserDto, // 👇 the Mapping we are extending
    extend(baseMapping)
);

// or
createMap(mapper, User, UserDto, extend(Base, BaseDto));

tip

We can still override the extended MappingProperties with forMember() after the extend()