try to snapshot schema

gatsby-node.js

@@ -1,24 +1,42 @@
-/**
- * Implement Gatsby's Node APIs in this file.
- *
- * See: https://www.gatsbyjs.org/docs/node-apis/
- */
+const { printType } = require("graphql")
+const fs = require("fs-extra")
+const path = require("path")
 
 exports.createResolvers = ({ createResolvers }) => {
   createResolvers({
     CommentsJson: {
       post: {
         type: `PostsJson`,
-        resolve (source, args, context, info) {
+        resolve(source, args, context, info) {
           const allNodes = context.nodeModel.getAllNodes()
           return allNodes
-            .filter(node => node.internal.type === 'PostsJson')
+            .filter(node => node.internal.type === "PostsJson")
             .find(page => {
               const parent = allNodes.find(n => n.id === page.parent)
               return parent && parent.name === source.postId
             })
-        }
-      }
-    }
+        },
+      },
+    },
   })
 }
+
+const schemaFilePath = path.join(__dirname, "./src/schema.gql")
+
+exports.sourceNodes = async ({ actions }) => {
+  const { createTypes } = actions
+
+  if (await fs.exists(schemaFilePath)) {
+    const typeDefs = (await fs.readFile(schemaFilePath)).toString()
+    createTypes(typeDefs)
+  }
+}
+
+exports.onPostBootstrap = async ({ store }) => {
+  const { schema } = store.getState()
+  const types = ["CommentsJson", "PostsJson"]
+  const typeDefs = types
+    .map(type => printType(schema.getType(type)))
+    .join("\n\n")
+  await fs.writeFile(schemaFilePath, typeDefs + "\n")
+}

src/schema.gql

@@ -0,0 +1,17 @@
+type CommentsJson implements Node {
+  id: ID!
+  parent: Node
+  children: [Node!]!
+  internal: Internal!
+  postId: String
+  message: String
+  post: PostsJson
+}
+
+type PostsJson implements Node {
+  id: ID!
+  parent: Node
+  children: [Node!]!
+  internal: Internal!
+  content: String
+}