Sort fix #698 [skip ci]

app/Generator/Chart/Basic/ChartJsGenerator.php

@@ -110,7 +110,12 @@ class ChartJsGenerator implements GeneratorInterface
         ];
 
         // sort by value, keep keys.
+        // different sort when values are positive and when they're negative.
         asort($data);
+        if(bccomp(next($data),'0') === 1) {
+            // next is positive, sort other way around.
+            arsort($data);
+        }
 
         $index = 0;
         foreach ($data as $key => $value) {