Hello!
It’s totally possible using the strapi.plugin('graphql').service('extension')
, you have an example in the user and permission plugin:
- https://github.com/strapi/strapi/blob/master/packages/plugins/users-permissions/server/register.js#L8-L10
- https://github.com/strapi/strapi/blob/master/packages/plugins/users-permissions/server/graphql/index.js#L10
Here is the related documentation: GraphQL - Strapi Developer Docs
But before getting deeper with GraphQL I recommend you to check this post before: Discussion regarding the complex response structure for REST & GraphQL (Developer Experience)
Hope this help!