Core: Support exportAs in remarkStructure.

.changeset/social-tips-ask.md

@@ -0,0 +1,5 @@
+---
+'fumadocs-core': patch
+---
+
+Support `exportAs` in `remarkStructure`.

packages/core/package.json

@@ -112,6 +112,7 @@
     "@orama/orama": "^3.1.16",
     "@shikijs/rehype": "^3.14.0",
     "@shikijs/transformers": "^3.14.0",
+    "estree-util-value-to-estree": "^3.5.0",
     "github-slugger": "^2.0.0",
     "hast-util-to-estree": "^3.1.3",
     "hast-util-to-jsx-runtime": "^2.3.6",

packages/core/src/mdx-plugins/mdast-utils.ts

@@ -0,0 +1,46 @@
+import type { RootContent } from 'mdast';
+import { valueToEstree } from 'estree-util-value-to-estree';
+
+export function flattenNode(node: RootContent): string {
+  if ('children' in node)
+    return node.children.map((child) => flattenNode(child)).join('');
+
+  if ('value' in node) return node.value;
+
+  return '';
+}
+
+export function toMdxExport(name: string, value: unknown): RootContent {
+  return {
+    type: 'mdxjsEsm',
+    value: '',
+    data: {
+      estree: {
+        type: 'Program',
+        sourceType: 'module',
+        body: [
+          {
+            type: 'ExportNamedDeclaration',
+            attributes: [],
+            specifiers: [],
+            source: null,
+            declaration: {
+              type: 'VariableDeclaration',
+              kind: 'let',
+              declarations: [
+                {
+                  type: 'VariableDeclarator',
+                  id: {
+                    type: 'Identifier',
+                    name,
+                  },
+                  init: valueToEstree(value),
+                },
+              ],
+            },
+          },
+        ],
+      },
+    },
+  };
+}

packages/core/src/mdx-plugins/remark-admonition.ts

@@ -1,7 +1,7 @@
 import { type Transformer } from 'unified';
 import { visit } from 'unist-util-visit';
 import { type Root, type RootContent } from 'mdast';
-import { flattenNode } from '@/mdx-plugins/remark-utils';
+import { flattenNode } from '@/mdx-plugins/mdast-utils';
 
 export interface RemarkAdmonitionOptions {
   tag?: string;

packages/core/src/mdx-plugins/remark-heading.ts

@@ -3,7 +3,7 @@ import type { Heading, Root } from 'mdast';
 import type { Transformer } from 'unified';
 import { visit } from 'unist-util-visit';
 import type { TOCItemType } from '@/toc';
-import { flattenNode } from '@/mdx-plugins/remark-utils';
+import { flattenNode } from '@/mdx-plugins/mdast-utils';
 
 const slugger = new Slugger();
 

packages/core/src/mdx-plugins/remark-structure.ts

@@ -4,7 +4,7 @@ import { remark } from 'remark';
 import remarkGfm from 'remark-gfm';
 import type { PluggableList, Transformer } from 'unified';
 import { visit } from 'unist-util-visit';
-import { flattenNode } from './remark-utils';
+import { flattenNode, toMdxExport } from './mdast-utils';
 import type {
   MdxJsxAttribute,
   MdxJsxExpressionAttribute,
@@ -49,14 +49,17 @@ export interface StructureOptions {
         node: MdxJsxFlowElement,
         attribute: MdxJsxAttribute | MdxJsxExpressionAttribute,
       ) => boolean);
+
+  /**
+   * export as `structuredData` or specified variable name.
+   */
+  exportAs?: string | boolean;
 }
 
 declare module 'mdast' {
   interface Data {
     /**
-     * Get content of unserializable element
-     *
-     * Needed for `remarkStructure` to generate search index
+     * [Fumadocs] Get content of unserializable element, `remarkStructure` uses it to generate search index.
      */
     _string?: string[];
   }
@@ -64,6 +67,9 @@ declare module 'mdast' {
 
 declare module 'vfile' {
   interface DataMap {
+    /**
+     * [Fumadocs] injected by `remarkStructure`
+     */
     structuredData: StructuredData;
   }
 }
@@ -84,6 +90,7 @@ export function remarkStructure({
 
     return ['TypeTable', 'Callout'].includes(node.name);
   },
+  exportAs = false,
 }: StructureOptions = {}): Transformer<Root, Root> {
   const slugger = new Slugger();
 
@@ -98,7 +105,7 @@ export function remarkStructure({
     types = (node) => arr.includes(node.type);
   }
 
-  return (node, file) => {
+  return (tree, file) => {
     slugger.reset();
     const data: StructuredData = { contents: [], headings: [] };
     let lastHeading: string | undefined;
@@ -117,9 +124,8 @@ export function remarkStructure({
       }
     }
 
-    visit(node, (element) => {
-      if (element.type === 'root') return;
-      if (!types(element)) return;
+    visit(tree, (element) => {
+      if (element.type === 'root' || !types(element)) return;
 
       if (element.type === 'heading') {
         element.data ||= {};
@@ -187,6 +193,14 @@ export function remarkStructure({
     });
 
     file.data.structuredData = data;
+    if (exportAs) {
+      tree.children.unshift(
+        toMdxExport(
+          typeof exportAs === 'string' ? exportAs : 'structuredData',
+          data,
+        ),
+      );
+    }
   };
 }
 

packages/core/src/mdx-plugins/remark-utils.ts

@@ -1,10 +0,0 @@
-import type { RootContent } from 'mdast';
-
-export function flattenNode(node: RootContent): string {
-  if ('children' in node)
-    return node.children.map((child) => flattenNode(child)).join('');
-
-  if ('value' in node) return node.value;
-
-  return '';
-}