diff --git a/lib/parse-diff.js b/lib/parse-diff.js
index 16bb65a..2e29ff8 100644
--- a/lib/parse-diff.js
+++ b/lib/parse-diff.js
@@ -16,7 +16,7 @@ function parseDiff (string) {
 }
 
 function fixParsedDiff (file) {
-  if (file.lines[0].content[0] === "@" && !file.lines[0].chunk) {
+  if (typeof file.lines[0] !== 'undefined' && file.lines[0].content[0] === "@" && !file.lines[0].chunk) {
     // Buggy
     file.lines = _.map(file.lines, fixDiffLine);
   }