node.js – How to manage multer fields if one of its field return null

I am using Multer in node js and i am using multer fields to upload profile picture and cover picture

fields( ( { name: ‘profile’, maxCount: 1 }, { name: ‘cover’, maxCount: 1 } ) );

i want to allow field if one of them is existed e.g if user is not uploading cover profile how I can manage other field of multer if it’s not exist?