Chart.js: Enable tick mirror option for X axes

[benfrain]

First of all

Thanks for a GREAT library. Having a lot of fun using this. Thanks for everyones effort.

Issue

When I set the xAxis tick configuration to be mirror: true I don't see the ticks mirrored. I think my config is correct but I'm a newbie here so hopefully I haven't committed a school boy error!

Codepen reduction

https://codepen.io/benfrain/pen/xrmzdE

Config used

var drawChart = function() {
  var ctx = document.getElementById("chtChart").getContext("2d");
  myChart = new Chart(ctx, {
    type: "line",
    data: {
      labels: ["6", "5", "4", "3", "2", "Yesterday", "Today"],

      datasets: [
        {
          label: "metric",
          data: [3, 2, 6, 5, 3, 4, 8],
          backgroundColor: "rgba(74, 207, 165, 0.1)",
          borderColor: "rgb(74, 207, 165)",
          borderWidth: 2,
          lineTension: 0,
          pointBackgroundColor: "rgb(74, 207, 165)",
          yAxisID: "y-axis-0",
        },
      ],
    },
    options: {
      layout: {
        padding: {
          left: -10,
          right: 0,
          top: 10,
          bottom: 10,
        },
      },
      scales: {
        yAxes: [
          {
            ticks: {
              beginAtZero: false,
              mirror: true,
            },
            gridLines: {
              display: true,
              borderDash: [4, 4],
              color: "rgba(64,64,64,100)",
            },
          },
        ],
        xAxes: [
          {
            display: true,
            gridLines: {
              display: false,
            },
            ticks: {
              beginAtZero: true,
              mirror: true,
            },
          },
        ],
      },
      legend: {
        display: false,
      },
    },
  });
};

drawChart();

Expected

With that config I was expecting the xAxis to display inside the chart area

Current Behaviour

The tick are displaying outside the chart area

Context

Chrome or Safari
Chartjs v2.6.0

[etimberg]

I think at the moment on vertical axes support mirroring. Should not be hard to implement for horizontal axes as well.