diff --git a/lib/6to5/generation/generators/types.js b/lib/6to5/generation/generators/types.js
index b9fa822ce3..4a58375a8d 100644
--- a/lib/6to5/generation/generators/types.js
+++ b/lib/6to5/generation/generators/types.js
@@ -84,8 +84,8 @@ exports.Literal = function (node) {
   if (type === "string") {
     val = JSON.stringify(val);
 
-    // escape unicode characters
-    val = val.replace(/[\u007f-\uffff]/g, function (c) {
+    // escape illegal js but valid json unicode characters
+    val = val.replace(/[\u000A\u000D\u2028\u2029]/g, function (c) {
       return "\\u" + ("0000" + c.charCodeAt(0).toString(16)).slice(-4);
     });