if else condition based update status in mongodb

not working this any other solution..

findOneAndUpdate( {"_id": ObjectId("5714ce0a4514ef3ef68677fd")}, $cond: { if: { $eq: [ "$isRequired", true ] }, then: { "status": "Done" }, else: { { "status": "Approved" } } )

same collection status update based on isRequire is true or false.