How do I correctly type the Apollo Client defaultOptions?

Question

I'm setting up Apollo Client like this.

const defaultOptions = {
  watchQuery: {
    fetchPolicy: 'cache-and-network',
    errorPolicy: 'ignore',
  },
  query: {
    fetchPolicy: 'cache-and-network',
    errorPolicy: 'all',
  },
  mutate: {
    errorPolicy: 'all',
  },
};
return new ApolloClient({
  link: ApolloLink.from([authLink, errorLink, webSocketOrHttpLink]),
  defaultOptions, // Typescript don't like this.
  queryDeduplication: true,
});

Typescript gives this error:

Type '{ watchQuery: { fetchPolicy: string; errorPolicy: string; }; query: { fetchPolicy: string; errorPolicy: string; }; mutate: { errorPolicy: string; }; }' is not assignable to type 'DefaultOptions'.ts(2322)
ApolloClient.d.ts(23, 5): The expected type comes from property 'defaultOptions' which is declared here on type 'ApolloClientOptions<NormalizedCacheObject>'

Per the docs, this is how it's supposed to be done.

How can I structure defaultOptions with proper types?

Answer 1

if you check code of library then , it seems here is issue

//defination of default options
export interface DefaultOptions {
 watchQuery?: Partial<WatchQueryOptions>;
 query?: Partial<QueryOptions>;
 mutate?: Partial<MutationOptions>;  
}

//defination of QueryOptions
export interface QueryOptions<TVariables = OperationVariables>
  extends QueryBaseOptions<TVariables> {
  /**
   * Specifies the {@link FetchPolicy} to be used for this query
   */
  fetchPolicy?: FetchPolicy;
}

//valid value for FetchPolicy type 
export type FetchPolicy =
  | 'cache-first'
  | 'network-only'
  | 'cache-only'
  | 'no-cache'
  | 'standby';

export type WatchQueryFetchPolicy = FetchPolicy | 'cache-and-network';

so here for query options you should pass any valid value for FetchPolicy and 'cache-and-network' is not valid value.

check documentation here : https://github.com/apollographql/apollo-client/blob/main/src/core/watchQueryOptions.ts