From d79f210aba670aab650b51f4ba0882e37949c330 Mon Sep 17 00:00:00 2001
From: Tony Brix <tony@brix.ninja>
Date: Sat, 14 Nov 2020 20:03:39 -0600
Subject: [PATCH] fix: no strikethrough on different number of tildes (#1821)

Possible Breaking Change: When using the inline.del rule the text is provided in capture group 2 instead of 1.
---
 src/Tokenizer.js                      |  2 +-
 src/rules.js                          |  4 ++--
 test/specs/new/del_strikethrough.html | 16 ++++++++++++++++
 test/specs/new/del_strikethrough.md   | 16 ++++++++++++++++
 4 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 test/specs/new/del_strikethrough.html
 create mode 100644 test/specs/new/del_strikethrough.md

diff --git a/src/Tokenizer.js b/src/Tokenizer.js
index 71b1916eda..e7d71fe027 100644
--- a/src/Tokenizer.js
+++ b/src/Tokenizer.js
@@ -585,7 +585,7 @@ module.exports = class Tokenizer {
       return {
         type: 'del',
         raw: cap[0],
-        text: cap[1]
+        text: cap[2]
       };
     }
   }
diff --git a/src/rules.js b/src/rules.js
index 8b0aa722fc..13356df367 100644
--- a/src/rules.js
+++ b/src/rules.js
@@ -318,8 +318,8 @@ inline.gfm = merge({}, inline.normal, {
   _extended_email: /[A-Za-z0-9._+-]+(@)[a-zA-Z0-9-_]+(?:\.[a-zA-Z0-9-_]*[a-zA-Z0-9])+(?![-_])/,
   url: /^((?:ftp|https?):\/\/|www\.)(?:[a-zA-Z0-9\-]+\.?)+[^\s<]*|^email/,
   _backpedal: /(?:[^?!.,:;*_~()&]+|\([^)]*\)|&(?![a-zA-Z0-9]+;$)|[?!.,:;*_~)]+(?!$))+/,
-  del: /^~+(?=\S)([\s\S]*?\S)~+/,
-  text: /^(`+|[^`])(?:(?= {2,}\n)|[\s\S]*?(?:(?=[\\<!\[`*~]|\b_|https?:\/\/|ftp:\/\/|www\.|$)|[^ ](?= {2,}\n)|[^a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-](?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@))|(?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@))/
+  del: /^(~~?)(?=[^\s~])([\s\S]*?[^\s~])\1(?=[^~]|$)/,
+  text: /^([`~]+|[^`~])(?:(?= {2,}\n)|[\s\S]*?(?:(?=[\\<!\[`*~]|\b_|https?:\/\/|ftp:\/\/|www\.|$)|[^ ](?= {2,}\n)|[^a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-](?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@))|(?=[a-zA-Z0-9.!#$%&'*+\/=?_`{\|}~-]+@))/
 });
 
 inline.gfm.url = edit(inline.gfm.url, 'i')
diff --git a/test/specs/new/del_strikethrough.html b/test/specs/new/del_strikethrough.html
new file mode 100644
index 0000000000..980134aa21
--- /dev/null
+++ b/test/specs/new/del_strikethrough.html
@@ -0,0 +1,16 @@
+<p><del>test</del></p>
+
+<p>~~test~</p>
+
+<p>~test~~</p>
+
+<p><del>test</del></p>
+
+<p><del>test
+test</del></p>
+
+<p>~~test</p>
+
+<p>test~~</p>
+
+<pre><code class="language-test~~~"></code></pre>
diff --git a/test/specs/new/del_strikethrough.md b/test/specs/new/del_strikethrough.md
new file mode 100644
index 0000000000..f3d5bca081
--- /dev/null
+++ b/test/specs/new/del_strikethrough.md
@@ -0,0 +1,16 @@
+~~test~~
+
+~~test~
+
+~test~~
+
+~test~
+
+~~test
+test~~
+
+~~test
+
+test~~
+
+~~~test~~~