_fine-grained-optimistic.md

Automatic optimistic update is convenient, but there might be cases where you want to explicitly control how the update happens. You can use the optimisticUpdateProvider callback to fully customize how each query cache entry should be optimistically updated. When the callback is set, it takes precedence over the automatic optimistic logic.

client.post.useCreate({
  optimisticUpdateProvider: ({ queryModel, queryOperation, queryArgs, currentData, mutationArgs }) => {
    return { kind: 'Update', data: ... /* computed result */ };
  }
});

The callback is invoked for each query cache entry and receives the following arguments in a property bag:

• queryModel: The model of the query, e.g., Post.
• queryOperation: The operation of the query, e.g., findMany, count.
• queryArgs: The arguments of the query, e.g., { where: { published: true } }.
• currentData: The current cache data.
• mutationArgs: The arguments of the mutation, e.g., { data: { title: 'My awesome post' } }.

It should return a result object with the following fields:

• kind: The kind of the optimistic update.
  • Update: update the cache using the computed data
  • Skip: skip the update
  • ProceedDefault: use the default automatic optimistic behavior.
• data: The computed data to update the cache with. Only used when kind is Update.