mutation-schema.js

let PostMutationType = new GraphQLObjectType({
  name: 'PostType',
  fields: () => ({
    like: {
      type: PostLikeType,
      args: {
        postId: {
          name: 'postId',
          type: GraphQLInt
        }
      },
      resolve: (user, {postId}) => {
        return PostService.likePost({
          userId: user.id,
          postId
        });
      }
    },
    unlike: {
      type: GraphQLInt,
      args: {
        postId: {
          name: 'postId',
          type: GraphQLInt
        }
      },
      resolve: (user, {postId}) => {
        return PostService.unlikePost({
          userId: user.id,
          postId
        });
      }
    }
  })
});

let MutationQueryType = new GraphQLObjectType({
  name: 'MutationQueries',
  fields: () => ({
    post: {
      type: PostMutationType,
      resolve: (user) => user
    }
  })
});

let SessionQuery = new GraphQLObjectType({
  name: 'MutationQuery',
  fields: () => ({
    data: {
      type: MutationQueryType,
      args: {
        id: {
          name: 'id',
          type: GraphQLInt
        }
      },
      resolve: (root, {id}) => {
        return new User({id})
        .fetch()
        .then(user => {
          if (user) {
            return user.toJSON();
          } else {
            return {};
          }
        });
      }
    }
  })
});

let schema = new GraphQLSchema({
  mutation: SessionQuery
});