Update gatsby local search to also include headers

config/search.js

@@ -16,19 +16,40 @@ const searchPluginConfig = {
             fields {
               path
             }
+            tableOfContents
           }
         }
       }
     `,
     index: ["title"],
     normalizer: ({ data }) =>
-      data.allMdx.nodes.map((node) => ({
-        id: node.id,
-        title: node.frontmatter.title,
-        description: node.frontmatter.description,
-        url: node.fields.path,
-        isExternal: false,
-      })),
+      data.allMdx.nodes.flatMap((node) => {
+        // return at least the main page ("node")
+        const returnVal = [
+          {
+            id: node.id,
+            title: node.frontmatter.title,
+            description: node.frontmatter.description,
+            url: node.fields.path,
+            isExternal: false,
+            toc: node.tableOfContents,
+          },
+        ];
+
+        // add the headers  too if they're in ToC
+        if (node.tableOfContents.items != null) {
+          node.tableOfContents.items.map((header) =>
+            returnVal.push({
+              id: node.id.concat(header.url),
+              title: node.frontmatter.title.concat(" - ", header.title),
+              url: node.fields.path.concat(header.url),
+              isExternal: false,
+            })
+          );
+        }
+
+        return returnVal;
+      }),
   },
 };