diff --git a/lib/markdown/index.js b/lib/markdown/index.js
index e945e550df..82b43e6d76 100644
--- a/lib/markdown/index.js
+++ b/lib/markdown/index.js
@@ -8,6 +8,7 @@ const emoji = require('markdown-it-emoji')
 const anchor = require('markdown-it-anchor')
 const toc = require('markdown-it-table-of-contents')
 const _slugify = require('./slugify')
+const { parseHeaders } = require('../util')
 
 module.exports = ({ markdown = {}} = {}) => {
   // allow user config slugify
@@ -37,7 +38,8 @@ module.exports = ({ markdown = {}} = {}) => {
     }, markdown.anchor))
     .use(toc, Object.assign({
       slugify,
-      includeLevel: [2, 3]
+      includeLevel: [2, 3],
+      format: parseHeaders
     }, markdown.toc))
 
   // apply user config
diff --git a/lib/util/index.js b/lib/util/index.js
index 4ef2345ad9..b9266dc85e 100644
--- a/lib/util/index.js
+++ b/lib/util/index.js
@@ -1,6 +1,8 @@
 const spawn = require('cross-spawn')
 const parseHeaders = require('./parseHeaders')
 
+exports.parseHeaders = parseHeaders
+
 exports.normalizeHeadTag = tag => {
   if (typeof tag === 'string') {
     tag = [tag]