Remove Local resolver support from the core of Apollo Client

[jpvajda]

Local resolvers are still available in Apollo Client 3, but they are deprecated. We recommend using field policies instead, as described in Local-only fields.

Local resolver support will be removed from the core of Apollo Client in a Major release and in a future major release it will be possible to achieve the functionality of local resolvers using an ApolloLink, as described in this issue.

References

• https://www.apollographql.com/docs/react/local-state/local-resolvers/
• Release local resolvers back into the link chain #10060
• Deprecation of local resolvers makes adopting GQL more difficult #7072
• Feature: Opt-in to including Apollo Client local resolver code in your bundle #8189