Extend graphql return mode to include the response when transport is http

[jasonkuhrt]

Perceived Problem

• I want the GraphQLClient instance to return response headers along with data #641

Ideas / Proposed Solution(s)

This is the current Graffle return mode system:

Mode	Throw Sources (no type safety)	Returns (type safe)
graphql	Extensions, Fetch	GraphQLExecutionResult
graphqlSuccess	Extensions, Fetch, GraphQLExecutionResult.errors	GraphQLExecutionResult with .errors always missing.
data (default)	Extensions, Fetch, GraphQLExecutionResult.errors	GraphQLExecutionResult.data
dataSuccess	Extensions, Fetch, GraphQLExecutionResult.errors, GraphQLExecutionResult.data Schema Errors	GraphQLExecutionResult.data without any schema errors
dataAndErrors		GraphQLExecutionResult.data, errors from: Extensions, Fetch, GraphQLExecutionResult.errors

I think it's fair to start with permitting response access in the low level escape hatch mode of graphql and graphqlSuccess. We can make the presence of response type safe based on client config (the transport).

We would be extending the native GraphQLExectionResult type so wherever that type is expected in the ecosystem the results of a raw Graffle request would still conform to the interface, the extra response field just being ignored.

I don't think the extensions field is the right place for this but I should double check actually, because I'm realizing now I'm not sure what the extensions field was really for.

[jasonkuhrt]

After some reflection I think the design of return mode needs to change into a more granular output settings:

Graffle.create({
  output: {
    response: true,
    extensions: true,
    throw: {
      schemaErrors: true,
      executionErrors: true,
      otherErrors: true,
    },
  },
})

We can still ship the currently defined return modes as pre-configured objects, sets of common patterns, for immediate use. Or perhaps the input type for this field accepts a union of either the object or an alias of a pre configuration. E.g.:

Graffle.create({
  output: 'graphql' | 'graphqlSuccess' | ...
})