Migrating to AutoMapper 8

A concise reference for the functional API introduced in AutoMapper TypeScript 8.

Version 8 replaced the fluent API with standalone mapping-configuration functions and renamed mapping plugins to strategies. If you are upgrading from v7 or earlier, make these changes before applying the v9 migration.

Mapper and strategy

// v7
const mapper = createMapper({
  name: 'default',
  pluginInitializer: classes,
});

// v8+
const mapper = createMapper({
  strategyInitializer: classes(),
});

All official strategy initializers are invoked: classes(), pojos(), mikro(), and sequelize().

Mapping declarations

createMap() and configuration methods became standalone functions:

// v7
mapper
  .createMap(User, UserDto)
  .forMember((destination) => destination.name, mapFrom((source) => source.fullName));

// v8+
createMap(
  mapper,
  User,
  UserDto,
  forMember(
    (destination) => destination.name,
    mapFrom((source) => source.fullName),
  ),
);

The model identifier order is source then destination:

mapper.map(user, User, UserDto);

Profiles and mutation

Use standalone addProfile() and the dedicated mutation methods:

addProfile(mapper, userProfile);

mapper.mutate(user, existingDto, User, UserDto);
mapper.mutateArray(users, existingDtos, User, UserDto);

Metadata changes

@AutoMap({ typeFn: () => User }) became @AutoMap(() => User).
Arrays must identify their element type with @AutoMap(() => [User]).
POJO metadata is registered through PojosMetadataMap.create().
PojosMetadataMap.reset() clears registered POJO metadata for tests.

See the current classes strategy and POJOs strategy guides for supported syntax.