feat: support using titles instead of region names in markdown file inclusion

closes #4375
closes #4382

Co-authored-by: btea <2356281422@qq.com>

__tests__/e2e/markdown-extensions/header-include.md

@@ -0,0 +1,27 @@
+# header 1
+
+header 1 content
+
+## header 1.1
+
+header 1.1 content
+
+### header 1.1.1
+
+header 1.1.1 content
+
+### header 1.1.2
+
+header 1.1.2 content
+
+## header 1.2
+
+header 1.2 content
+
+### header 1.2.1
+
+header 1.2.1 content
+
+### header 1.2.2
+
+header 1.2.2 content

__tests__/e2e/markdown-extensions/index.md

@@ -213,6 +213,10 @@ export default config
 
 <!--@include: ./region-include.md#range-region{5,}-->
 
+## Markdown File Inclusion with Header
+
+<!--@include: ./header-include.md#header-1-1-->
+
 ## Image Lazy Loading
 
 ![vitepress logo](/vitepress.png)

docs/en/guide/markdown.md

@@ -897,6 +897,41 @@ You can also use a [VS Code region](https://code.visualstudio.com/docs/editor/co
 Note that this does not throw errors if your file is not present. Hence, when using this feature make sure that the contents are being rendered as expected.
 :::
 
+Instead of VS Code regions, you can also use header anchors to include a specific section of the file. For example, if you have a header in your markdown file like this:
+
+```md
+## My Base Section
+
+Some content here.
+
+### My Sub Section
+
+Some more content here.
+
+## Another Section
+
+Content outside `My Base Section`.
+```
+
+You can include the `My Base Section` section like this:
+
+```md
+## My Extended Section
+<!--@include: ./parts/basics.md#my-base-section-->
+```
+
+**Equivalent code**
+
+```md
+## My Extended Section
+
+Some content here.
+
+### My Sub Section
+
+Some more content here.
+```
+
 ## Math Equations
 
 This is currently opt-in. To enable it, you need to install `markdown-it-mathjax3` and set `markdown.math` to `true` in your config file:

src/node/markdownToVue.ts

@@ -142,7 +142,7 @@ export async function createMarkdownToVueRenderFn(
 
     // resolve includes
     let includes: string[] = []
-    src = processIncludes(srcDir, src, fileOrig, includes)
+    src = processIncludes(md, srcDir, src, fileOrig, includes)
 
     const localeIndex = getLocaleForPath(siteConfig?.site, relativePath)
 

src/node/plugins/localSearchPlugin.ts

@@ -56,7 +56,7 @@ export async function localSearchPlugin(
     const relativePath = slash(path.relative(srcDir, file))
     const env: MarkdownEnv = { path: file, relativePath, cleanUrls }
     const md_raw = await fs.promises.readFile(file, 'utf-8')
-    const md_src = processIncludes(srcDir, md_raw, file, [])
+    const md_src = processIncludes(md, srcDir, md_raw, file, [])
     if (options._render) {
       return await options._render(md_src, env, md)
     } else {

src/node/utils/processIncludes.ts

@@ -1,18 +1,20 @@
 import fs from 'fs-extra'
 import matter from 'gray-matter'
+import type { MarkdownItAsync } from 'markdown-it-async'
 import path from 'node:path'
 import c from 'picocolors'
 import { findRegion } from '../markdown/plugins/snippet'
 import { slash } from '../shared'
 
 export function processIncludes(
+  md: MarkdownItAsync,
   srcDir: string,
   src: string,
   file: string,
   includes: string[]
 ): string {
   const includesRE = /<!--\s*@include:\s*(.*?)\s*-->/g
-  const regionRE = /(#[\w-]+)/
+  const regionRE = /(#\S+)/
   const rangeRE = /\{(\d*),(\d*)\}$/
 
   return src.replace(includesRE, (m: string, m1: string) => {
@@ -39,8 +41,30 @@ export function processIncludes(
       if (region) {
         const [regionName] = region
         const lines = content.split(/\r?\n/)
-        const regionLines = findRegion(lines, regionName.slice(1))
-        content = lines.slice(regionLines?.start, regionLines?.end).join('\n')
+        let { start, end } = findRegion(lines, regionName.slice(1)) ?? {}
+
+        if (start === undefined) {
+          // region not found, it might be a header
+          const tokens = md
+            .parse(content, {})
+            .filter((t) => t.type === 'heading_open' && t.map)
+          const idx = tokens.findIndex(
+            (t) => t.attrGet('id') === regionName.slice(1)
+          )
+          const token = tokens[idx]
+          if (token) {
+            start = token.map![1]
+            const level = parseInt(token.tag.slice(1))
+            for (let i = idx + 1; i < tokens.length; i++) {
+              if (parseInt(tokens[i].tag.slice(1)) <= level) {
+                end = tokens[i].map![0] - 1
+                break
+              }
+            }
+          }
+        }
+
+        content = lines.slice(start, end).join('\n')
       }
 
       if (range) {
@@ -48,8 +72,8 @@ export function processIncludes(
         const lines = content.split(/\r?\n/)
         content = lines
           .slice(
-            startLine ? parseInt(startLine, 10) - 1 : undefined,
-            endLine ? parseInt(endLine, 10) : undefined
+            startLine ? parseInt(startLine) - 1 : undefined,
+            endLine ? parseInt(endLine) : undefined
           )
           .join('\n')
       }
@@ -60,7 +84,7 @@ export function processIncludes(
 
       includes.push(slash(includePath))
       // recursively process includes in the content
-      return processIncludes(srcDir, content, includePath, includes)
+      return processIncludes(md, srcDir, content, includePath, includes)
 
       //
     } catch (error) {