[BUG] Updating ticks fontColor is not working

[uffou]

I am attempting to update scales ticks and grid lines to be visible only on hover. It works for the grid lines but it does not work for the ticks. Changing with display works but it is not suitable because it changes the width of the chart.
Interactive demo: https://codepen.io/uffou/pen/zpdZVb

Expected Behavior

Current Behavior

[simonbrunel]

Looks like a bug, need investigation, we might cache some options that are not correctly updated.

[jcopperfield]

@uffou I think this is the same problem as #4896
There isn't a real bugfix, however you could use myChart.options.scales.yAxes[0].ticks.minor.fontColor as a workaround.

ctx.addEventListener('mouseenter', function(){
  myChart.options.scales.yAxes[0].gridLines.color = `red`;
  myChart.options.scales.yAxes[0].ticks.minor.fontColor = `red`;
  myChart.update();
});
ctx.addEventListener('mouseleave', function(){
  myChart.options.scales.yAxes[0].gridLines.color = `rgba(0,0,0,0)`;
  myChart.options.scales.yAxes[0].ticks.minor.fontColor = `rgba(0,0,0,0)`;
  myChart.update();
});

[uffou]

@jcopperfield thanks! that works 🎉

[simonbrunel]

Thanks @jcopperfield, closing as duplicated of #4896.

We should avoid modifying the user given options object to store minor/major values from the ticks.* ones, but instead work on the clone of the scale options. That should ensure that minor/major are recalculated at each update.