How to ignore source's unmapped fields?

[zwjohn]

Hi,
I am using AutoMapper in NestJS, and I noticed that unmapped fields in the nested object from the source are added to the destination's nested object. How do I ignore these unmapped fields?

Thanks!

[milosdakic]

When you say "unmapped fields in the nested object from the source are added to the destination's nested object" do you mean they are coming back as undefined or similar?