indexLabelBorderThickness: Number

Sets the Border Thickness of Index Labels in datapoint level.

var  chart =  new  CanvasJS.Chart("container", {
 .
 .
 data: [{
   { y: 10, indexLabel:"apple", indexLabelBorderThickness: 1, indexLabelBorderColor: "red" },
 }]
 .
 . 
});
chart.render();