Feature request: adding path to estimators args(for calculating actual query complexity)

[eduhenke]

I want to have both the expected and actual query complexity/cost, like in the shopify api: https://shopify.dev/api/usage/rate-limits#requested-and-actual-cost.

The expected query cost is pretty easy with this library, an example using an ApolloServer plugin:

{
  requestDidStart: async () => ({
    async didResolveOperation({ request, document }) {
      const complexity = getComplexity({
        schema,
        operationName: request.operationName,
        query: document,
        variables: request.variables,
        estimators: [
          directiveEstimator({ name: 'complexity' }),
          simpleEstimator({ defaultComplexity: 1 }),
        ],
      });
      logger.info('Expected query complexity points:', { complexity });
    }
  })
}

However, I'm having trouble calculating the actual query cost, here is my attempt so far:

{
  requestDidStart: async () => ({
    async willSendResponse({ request, document, response }) {
      // uses response objects to determine the actual operation complexity
      const responseEstimator: ComplexityEstimator = (options) => {
        // there is no "options.path"
        // const object = _.get(response, options.path);
        // i can then use object.length(or something else) to get the number of returned items
        // return object.length ?? 1;
        return 1;
      };
      const complexity = getComplexity({
        schema,
        operationName: request.operationName,
        query: document!,
        variables: request.variables,
        estimators: [responseEstimator],
      });
      logger.info('Actual query complexity points:', { complexity });
    },
  })
}

It seems for this implementation to work I'd need access to the path of the field, like in https://github.com/graphql/graphql-js/blob/main/src/type/definition.ts#L896 or the fourth field on the resolvers(info.path), so I can map the field in which the complexity is being calculated to the actual response