proto3 field without field presence cannot be null

[ramkumarka...@gmail.com]

Hi 

I am implementing grpc on nodejs framework. I already have a database of my data and where some fields contain null values and also array fields also empty for some documents. So here is the problem while retrieving data from mongodb using grpc. It throwing an error proto3 field without field presence cannot be null). can anyone help me on how to fix this in proto file, not to throw error if fields are empty. Currently I'm using grpc package. 

Thanks, 

Ram Kumar K