fix for issue 380 from adilh

diff --git a/dygraph.js b/dygraph.js
index 0fc48ce..621ea32 100644 (file)
--- a/dygraph.js
+++ b/dygraph.js
@@ -1536,7 +1536,8 @@ Dygraph.prototype.doUnzoom_ = function() {
       newValueRanges = [];
       for (i = 0; i < this.axes_.length; i++) {
         var axis = this.axes_[i];
-        newValueRanges.push(axis.valueRange !== null ?
+        newValueRanges.push((axis.valueRange !== null &&
+                             axis.valueRange !== undefined) ?
                             axis.valueRange : axis.extremeRange);
       }
     }