Change `optimisticResponse` type to be consistent and less restrictive. (#6643)
Change `optimisticResponse` type to be consistent and less restrictive. (#6643)

Per https://github.com/apollographql/apollo-client/issues/6390, the extra `| {}` makes certain semantically correct patterns that used to be okay in Typescript 3.7 illegal in 3.9. The difference between the two definitions of `optimisticResponse` in this file appears to have been a simple oversight when they were added in https://github.com/apollographql/react-apollo/pull/3257.
apollostack/apollo-client,apollographql/apollo-client,apollographql/apollo-client,apollostack/apollo-client,apollostack/apollo-client