Related Content

exports.createSchemaCustomization = ({ actions, schema }) => {
  actions.createTypes([
    schema.buildObjectType({
      interfaces: ["Node"],
      name: "SanityPost",
      fields: {
        relatedPosts: {
          type: "[SanityPost]",
          resolve: async (source, args, context, info) => {
            const categories = source._rawDataCategories
              ? source._rawDataCategories.map((c) => c._ref)
              : [];
            if (!categories.length) return [];

            const posts = await context.nodeModel.runQuery({
              query: {
                filter: {
                  categories: {
                    elemMatch: {
                      _id: { in: categories },
                    },
                  },
                  // exclude current node
                  _id: { ne: source._id },
                },
                sort: {
                  fields: ["publishedAt"],
                  order: ["DESC"],
                },
                // no way to limit results in runQuery
                // see: https://github.com/gatsbyjs/gatsby/issues/15453
              },
              type: "SanityPost",
            });

            return posts && posts.length > 0 ? posts : [];
          },
        },
      },
    })
  ]);
};