Avoid error if borderOpts.dash is undefined (#11907)

diff --git a/src/scales/scale.radialLinear.js b/src/scales/scale.radialLinear.js
index 642fa1c140f46fbd3abe83f861d4f34e46495814..0a2c61f722b38ee348bec6e3ceaebb838b7ff553 100644 (file)
--- a/src/scales/scale.radialLinear.js
+++ b/src/scales/scale.radialLinear.js
@@ -317,7 +317,7 @@ function drawRadiusLine(scale, gridLineOpts, radius, labelCount, borderOpts) {
   ctx.save();
   ctx.strokeStyle = color;
   ctx.lineWidth = lineWidth;
-  ctx.setLineDash(borderOpts.dash);
+  ctx.setLineDash(borderOpts.dash || []);
   ctx.lineDashOffset = borderOpts.dashOffset;
 
   ctx.beginPath();