From 83ba338bd0e59267080c37bd235e1b0a601edf36 Mon Sep 17 00:00:00 2001
From: Mihai Bazon <mihai@bazon.net>
Date: Fri, 6 Sep 2013 10:10:45 +0300
Subject: [PATCH] Avoid printing <!-- in the output (HTML5 comment)

---
 lib/output.js | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/output.js b/lib/output.js
index df2692ad..e7f3f4dd 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -989,7 +989,18 @@ function OutputStream(options) {
         self.left.print(output);
         output.space();
         output.print(self.operator);
-        output.space();
+        if (self.operator == "<"
+            && self.right instanceof AST_UnaryPrefix
+            && self.right.operator == "!"
+            && self.right.expression instanceof AST_UnaryPrefix
+            && self.right.expression.operator == "--") {
+            // space is mandatory to avoid outputting <!--
+            // http://javascript.spec.whatwg.org/#comment-syntax
+            output.print(" ");
+        } else {
+            // the space is optional depending on "beautify"
+            output.space();
+        }
         self.right.print(output);
     });
     DEFPRINT(AST_Conditional, function(self, output){
-- 
2.34.1