diff --git a/js/diagrams.js b/js/diagrams.js
index 0076e29..ff5d0b8 100644
--- a/js/diagrams.js
+++ b/js/diagrams.js
@@ -2,8 +2,18 @@
 
 // https://bl.ocks.org/mbostock/3884955
 function createLineGraph(containerId, raceData){
-  console.log(raceData);
+  // Rough input validation
+  if(raceData.raceInfo === undefined) {
+    console.error(["Sorry, that raceData is empty. :-(", raceData]);
+    return; // early return to avoid errors
+  } else {
+    console.log(raceData);
+  }
 
+  var enhancedLapData = processor.getEnhancedLapDataPerDriver(raceData);
+  console.log(enhancedLapData);
+
+  // Configuration
   var height = 720;
   var width = 1080;
   var linePointSize = 5;
@@ -37,9 +47,6 @@ function createLineGraph(containerId, raceData){
   x.domain([0, raceData.lapTimes.size]);
   y.domain([raceData.drivers.length, 1]);
 
-  var enhancedLapData = processor.getEnhancedLapDataPerDriver(raceData);
-  console.log(enhancedLapData);
-
   // Adds all lines
   enhancedLapData.forEach((driverLapData, driverIndex) => {
     //console.log(driverLapData);