From ad83169fae78e67808f8831385a904d6ef56e11a Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Wed, 18 Apr 2018 11:31:03 -0400
Subject: [PATCH] fix: handle headers that start with numbers (fix #121)

---
 lib/markdown/slugify.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/markdown/slugify.js b/lib/markdown/slugify.js
index d4aa023412..47a9d6e9de 100644
--- a/lib/markdown/slugify.js
+++ b/lib/markdown/slugify.js
@@ -15,6 +15,8 @@ module.exports = function slugify (str) {
     .replace(/\-{2,}/g, '-')
     // Remove prefixing and trailing separtors
     .replace(/^\-+|\-+$/g, '')
+    // ensure it doesn't start with a number (#121)
+    .replace(/^(\d)/, '_$1')
     // lowercase
     .toLowerCase()
 }