AutoMapper 9

AutoMapper 9 moves the package family to a modern ESM and Node.js baseline, adds genuine asynchronous mapping, and introduces stronger runtime contracts.

Highlights

• Async map and mutation APIs now await promise-returning member resolvers and lifecycle callbacks.
• NestJS MapInterceptor and MapPipe await asynchronous object and array mappings.
• beforeMapArray() and afterMapArray() configure collection-wide lifecycle work.
• AutoMapperError, MappingNotFoundError, and MapMemberError make mapper failures distinguishable and inspectable.
• AutoMapperLogger supports additional log levels, repeatable configuration, restoration, and reset.
• Class identifiers accept abstract classes and classes with non-public constructors.
• Mapping plans are compiled when mappings are created, reducing repeated per-object work.

Compatibility

• Node.js 20 or later is required.
• Packages are ESM-only.
• NestJS 10 and 11 are supported.
• MikroORM 6 is supported.
• Sequelize 6 remains supported.
• reflect-metadata 0.1.14 and 0.2 releases are accepted.

Read Migrating to AutoMapper 9 for code examples and the upgrade checklist.