diff --git a/lib/output.js b/lib/output.js
index 764b8e36..ddc28820 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -1262,16 +1262,18 @@ function OutputStream(options) {
         }
     });
 
+    var xml_unsafe = [
+        // all C0 characters except tab, newline and return are invalid
+        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+        0x08, 0x0c, 0x0e, 0x0f,
+        0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+        0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+        0xfffe, 0xffff
+    ];
+
     function regexp_safe_literal(code, xml_safe) {
         if (xml_safe) {
-            if ([
-                // all C0 characters except tab, newline and return are invalid
-                0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
-                0x08, 0x0c, 0x0e, 0x0f,
-                0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
-                0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-                0xfffe, 0xffff
-            ].indexOf(code) >= 0)
+            if (xml_unsafe.indexOf(code) >= 0)
                 return false;
             // C1 (except 0x85) and surrogate pair code points are invalid
             if ((code >= 0x7f && code != 0x85 && code <= 0x9f)