1 files changed, 7 insertions, 1 deletions
diff --git a/lib/smtpapi_headers.js b/lib/smtpapi_headers.js
index 4bd8a15..f15cd57 100644
--- a/lib/smtpapi_headers.js
+++ b/lib/smtpapi_headers.js
@@ -65,7 +65,13 @@ SmtpapiHeaders.prototype.addFilterSetting = function(filter, setting, val) {
 }
 
 SmtpapiHeaders.prototype.toJson = function() {
-  var json = JSON.stringify(this);
+  var data = _.clone(this);
+  _.each(data, function(v, k, list) {
+    if (_.isEmpty(v)) {
+      delete list[k];
+    }
+  });
+  var json = JSON.stringify(data);
   return json.replace(/(["\]}])([,:])(["\[{])/, '$1$2 $3');
 }