Fixed error when adding a new entry.

src/html/js/entries.js

@@ -179,7 +179,9 @@ var ListViewModel = function() {
       // Transform to an array readable by jqplot Line renderer.
       var chartValues = [];
       $.each(entries, function(index, entry) {
+        if(entry.value_date && unwrap(entry.value_date)) {
           chartValues.push([unwrap(entry.value_date), Number(unwrap(entry.sold))]);
+        }
       });
 
       return chartValues;