ApolloGraphQL -- ReadQuery `Field Not Found` Error?

Question

My readQuery is returning a field not found error, even though it seems like the field is present in the cache.

QUERY

const GETIMSFROMCACHE_QUERY = gql`
query getIMsFromCache($fromID: String!){
  instant_message(fromID:$fromID){
    id,
    fromID,
    toID,
    msgText
  }
}  `;

CACHE RESOLVER

client.cache.cacheResolvers = {
    Query: {
        instant_message: (_, args) => toIdValue(client.dataIdFromObject({
            __typename: 'instant_message',
            id: args.id
        })),
    },
};

READQUERY CALL, IN UPDATE

let instant_message = cache.readQuery({ query: GETIMSFROMCACHE_QUERY, variables: {"fromID": fromID} });

ERROR

Error: Can't find field instant_message({"fromID":"ayqNLcA7c6r8vip3i"}) on object (ROOT_QUERY) {
  "getMyUserData({\"id\":\"ayqNLcA7c6r8vip3i\"})": [
    {
      "type": "id",
      "generated": false,
      "id": "MyUserData:ayqNLcA7c6r8vip3i",
      "typename": "MyUserData"
    }
  ],
  "getMyUserData({\"id\":\"9W95z8A7Y6i34buk7\"})": [
    {
      "type": "id",
      "generated": false,
      "id": "MyUserData:9W95z8A7Y6i34buk7",
      "typename": "MyUserData"
    }
  ],
  "Appts({\"originatingUserID\":\"ayqNLcA7c6r8vip3i\"})": [],
  "instant_message({\"fromID\":\"ayqNLcA7c6r8vip3i\",\"toID\":\"9W95z8A7Y6i34buk7\"})": [
    {
      "type": "id",
      "generated": false,
      "id": "instant_message:126",
      "typename": "instant_message"
    },
    {
      "type": "id",
      "generated": false,
      "id": "instant_message:127",
      "typename": "instant_message"
    },
    {
      "type": "id",
      "generated": false,
      "id": "instant_message:128",
      "typename": "instant_message"
    }
  ]
}.

Looking at the error message, there seems to be a instant_message object present on the ROOT_QUERY object with the target user id, but I'm getting this error.

How can I correct this?

Thanks in advance to all for any info.

Answer 1

Solved! This was tricky because the regular resolver for the original query, brings back any IM that is to or from either of the two users. The resolver returns any instant_messages that are from fromID and to toID, or vice-versa.

So I thought I needed some sort of cache resolver to repeat this when querying the cache.

Eventually I realized that the cache doesn't care what happened in the resolver -- it's going to store the instant_message objects as being from fromID and to toID, regardless of what happened in the resolver.

Once I realized that, I dropped the special cache resolver query, and just used the original query that retrieved the instant_messages in the first place, with the same query variables used with it in the first place, and it worked. :)