Configure the differences

Compute a member, convert a type, and enable convention-based flattening.

Compute fullName

Use forMember() to target one destination member and mapFrom() to select or compute its value.

createMap(
  mapper,
  User,
  UserDto,
  forMember(
    (destination) => destination.fullName,
    mapFrom((source) => `${source.firstName} ${source.lastName}`),
  ),
);

Convert birthday

A type converter applies to every matching source and destination member pair in that mapping.

createMap(
  mapper,
  Bio,
  BioDto,
  typeConverter(Date, String, (date) => date.toDateString()),
);

Use forMember() instead when only one destination member should use the conversion.

Flatten job

Auto-flattening splits destination names according to a configured naming convention. With camel case enabled, jobTitle can match job.title and jobSalary can match job.salary.

createMap(
  mapper,
  Bio,
  BioDto,
  typeConverter(Date, String, (date) => date.toDateString()),
  namingConventions(new CamelCaseNamingConvention()),
);

The completed mapping returns a DTO with copied, computed, converted, nested, and flattened members while keeping the source and destination classes independent.

Async values

In v9, mapFrom() may return a promise when you call mapAsync():

createMap(
  mapper,
  User,
  UserDto,
  forMember(
    (destination) => destination.fullName,
    mapFrom(async (source) => loadDisplayName(source.username)),
  ),
);

const dto = await mapper.mapAsync(user, User, UserDto);

Do not call synchronous map() for a mapping with asynchronous member resolvers.