···3232| `optimistic` | A mapping of mutation fields to resolvers that may be used to provide _Graphcache_ with an optimistic result for a given mutation field that should be applied to the cached data temporarily. |
3333| `schema` | A serialized GraphQL schema that is used by _Graphcache_ to resolve partial data, interfaces, and enums. The schema also used to provide helpful warnings for [schema awareness](../graphcache/schema-awareness.md). |
3434| `storage` | A persisted storage interface that may be provided to preserve cache data for [offline support](../graphcache/offline.md). |
3535+| `globalIDs` | A boolean or list of typenames that have globally unique ids, this changes how graphcache internally keys the entities. This can be useful for complex interface relationships. |
3536| `logger` | A function that will be invoked for warning/debug/... logs |
36373738The `@urql/exchange-graphcache` package also exports the `offlineExchange`; which is identical to