refactor(starter): upgrade to new version of gatsby

internal/gatsby/on-create-node.ts

@@ -0,0 +1,58 @@
+import { GatsbyNode } from "gatsby";
+import { createFilePath } from "gatsby-source-filesystem";
+
+import * as constants from "./constants";
+import * as types from "./types";
+import * as utils from "./utils";
+
+const onCreateNode: GatsbyNode["onCreateNode"] = ({
+  node,
+  actions,
+  getNode,
+}) => {
+  const { createNodeField } = actions;
+
+  if (node.internal.type === "MarkdownRemark") {
+    const { frontmatter, parent }: types.Edge["node"] = node;
+    const { tags, category, slug } = frontmatter || {};
+
+    if (slug) {
+      const dirname = parent && getNode(parent)?.relativeDirectory;
+      const value =
+        typeof dirname === "string"
+          ? utils.concat("/", dirname, "/", slug)
+          : utils.concat("/", slug);
+
+      createNodeField({ node, name: "slug", value });
+    } else {
+      const value = createFilePath({ node, getNode });
+      createNodeField({ node, name: "slug", value });
+    }
+
+    if (tags) {
+      const value = tags.map(tag =>
+        utils.concat(
+          constants.routes.tagRoute,
+          "/",
+          utils.toKebabCase(tag),
+          "/",
+        ),
+      );
+
+      createNodeField({ node, name: "tagSlugs", value });
+    }
+
+    if (category) {
+      const value = utils.concat(
+        constants.routes.categoryRoute,
+        "/",
+        utils.toKebabCase(category),
+        "/",
+      );
+
+      createNodeField({ node, name: "categorySlug", value });
+    }
+  }
+};
+
+export { onCreateNode };