1 files changed, 12 insertions, 3 deletions
diff --git a/js/binary/encoder.js b/js/binary/encoder.js
index 59c4ccb9..fe5e34e9 100644
--- a/js/binary/encoder.js
+++ b/js/binary/encoder.js
@@ -409,10 +409,19 @@ jspb.BinaryEncoder.prototype.writeFixedHash64 = function(hash) {
  */
 jspb.BinaryEncoder.prototype.writeString = function(value) {
   var oldLength = this.buffer_.length;
-
-  // UTF16 to UTF8 conversion loop swiped from goog.crypt.stringToUtf8ByteArray.
+ 
   for (var i = 0; i < value.length; i++) {
-    var c = value.codePointAt(i);
+    
+    var c = value.charCodeAt(i);
+    // Look for surrogates
+    if (c >= 0xD800 && c <= 0xDBFF && i + 1 < value.length) {
+      var second = value.charCodeAt(i + 1);
+      if (second >= 0xDC00 && second <= 0xDFFF) { // low surrogate
+        // http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
+        c = (c - 0xD800) * 0x400 + second - 0xDC00 + 0x10000;
+      }
+    }
+
     if (c < 128) {
       this.buffer_.push(c);
     } else if (c < 2048) {