diff --git a/lib/utils.js b/lib/utils.js
index 1e545381..c86b160f 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -161,17 +161,17 @@ var encode = function encode(str, defaultEncoder, charset, kind, format) {
         }
 
         if (c < 0x80) {
-            out = out + hexTable[c];
+            out += hexTable[c];
             continue;
         }
 
         if (c < 0x800) {
-            out = out + (hexTable[0xC0 | (c >> 6)] + hexTable[0x80 | (c & 0x3F)]);
+            out += hexTable[0xC0 | (c >> 6)] + hexTable[0x80 | (c & 0x3F)];
             continue;
         }
 
         if (c < 0xD800 || c >= 0xE000) {
-            out = out + (hexTable[0xE0 | (c >> 12)] + hexTable[0x80 | ((c >> 6) & 0x3F)] + hexTable[0x80 | (c & 0x3F)]);
+            out += hexTable[0xE0 | (c >> 12)] + hexTable[0x80 | ((c >> 6) & 0x3F)] + hexTable[0x80 | (c & 0x3F)];
             continue;
         }