diff --git a/lib/shared/markdown.js b/lib/shared/markdown.js
--- a/lib/shared/markdown.js
+++ b/lib/shared/markdown.js
@@ -250,6 +250,8 @@
   };
 }
 
+const spoilerRegex: RegExp = /^\|\|([^\n]+?)\|\|/g;
+
 export {
   paragraphRegex,
   paragraphStripTrailingNewlineRegex,
@@ -262,6 +264,7 @@
   codeBlockStripTrailingNewlineRegex,
   fenceRegex,
   fenceStripTrailingNewlineRegex,
+  spoilerRegex,
   matchBlockQuote,
   parseBlockQuote,
   jsonMatch,