Change the structure of a GraphQL response

Question

I have a GraphQL and Express project with these existing routes:

// ...

const graphiqlExpress = require('graphql-server-express').graphiqlExpress;
const graphqlExpress = require('graphql-server-express').graphqlExpress;
const makeExecutableSchema = require('graphql-tools').makeExecutableSchema;

// ...

const schema = makeExecutableSchema({
  typeDefs,
  resolvers,
});

// ...

app.use('/graphql', bodyParser.json(), graphqlExpress({ schema }));
app.use(
  '/graphiql',
  graphiqlExpress({
    endpointURL: '/graphql',
  })
);

My results after a GET on http://localhost:3030/graphql?query={regions(countries:["FR"],level:0){...} look like a normal GraphQL response:

{
  "data": {
    "regions": [
      {
        "type": "FeatureCollection",
        "features": [
          ...
          ...
        ]
      }
    ]
  }
}

Is there a way to transform the response to something more like a valid GeoJSON format? (no " data:{ } " and without the name of my query, etc.) such as:

{
  "type": "FeatureCollection",
    "features": [
      ...
      ...
    ]  
}

What I've already thought of doing is either using a middleare (but how?) and/or a normalizer such as graphql-normalizr (but I don't know how to plug it with Express)

Answer 1

After a few good hours of searching left and right I found a viable solution. Luckily there is a formatResponse that you can use: https://github.com/apollographql/apollo-server/blob/master/packages/apollo-server-core/src/graphqlOptions.ts#L43

The updated code looks like:

app.use(
  '/graphql',
  bodyParser.json(),
  graphqlExpress({ schema, formatResponse: res => (res.data.regions && res.data.regions[0]) || res })
);