Bail out, same as the x axis

diff --git a/src/core/core.scale.js b/src/core/core.scale.js
index edf807de07e882eda14592438b25df8d43fd4938..f40f6fa2d53447afa5b482b2505bbb888ba8161f 100644 (file)
--- a/src/core/core.scale.js
+++ b/src/core/core.scale.js
@@ -467,6 +467,11 @@
                                        var xTickEnd = this.options.position == "right" ? this.left + 5 : this.right;
 
                                        helpers.each(this.ticks, function(label, index) {
+                                               // If the callback returned a null or undefined value, do not draw this line
+                                               if (label === undefined || label === null) {
+                                                       return;
+                                               }
+
                                                var yLineValue = this.getPixelForTick(index); // xvalues for grid lines
 
                                                if (this.options.gridLines.show) {