no valLetter (no y) -> nullArray

Author: richardnm-2

devtools/test_dashboard/index.html

@@ -235,7 +235,11 @@
           yanchor: "bottom",
         },
       };
-      Plotly.newPlot("tester", data2);
+      // Plotly.newPlot("tester", data2);
+    </script>
+    <script>
+      let data3 = [{ x: ["a", "b", "c"], base: [0.2, -0.2, 1], type: "bar" }];
+      Plotly.newPlot("tester", data3);
     </script>
   </body>
 </html>

src/plots/cartesian/set_convert.js

@@ -407,9 +407,12 @@ module.exports = function setConvert(ax, fullLayout) {
                                 arrays.push(trace.z);
                             }
                             valLetter = 'z';
-                        } else {
+                        } else if(trace.y) {
                             arrays.push(trace.y);
                             valLetter = 'y';
+                        } else {
+                            var nullArray = arrayIn.map(function() {return null;});
+                            arrays.push(nullArray);
                         }
                         var objList = sortLib.matrixToObjectList(arrays, cols);