Correct Tooltip modification technique

I'm having an issue modifying the tooltip, I was requested to add dollar signs before each value, to do this I ended up pulling the default tooltip callback out of the Chart.BoxPlot.js file and modifying it in the options of my chart instance. However, this also required that I pull out the toFixed function as well.

This works, and I was able to add my dollar sign, but it felt a bit hacky, I was wondering if there is an intended procedure for this?

Codepen of this in action: https://codepen.io/djones4822/pen/MWmbBqa

Code used:

Extracted from BoxPlot, add anywhere in your js file:

  function toFixed(value) {
    var decimals = this._chart.config.options.tooltipDecimals; // inject number of decimals from config

    if (decimals == null || typeof decimals !== 'number' || decimals < 0) {
      return value;
    }

    return Number.parseFloat(value).toFixed(decimals);
  }

Add to the options section of the chart definition:

//existing options code
tooltips: {
        callbacks: {
          boxplotLabel: function boxplotLabel(
            item,
            data,
            b,
            hoveredOutlierIndex
          ) {
            var datasetLabel = data.datasets[item.datasetIndex].label || "";
            var label = ""
              .concat(datasetLabel, " ")
              .concat(
                typeof item.xLabel === "string" ? item.xLabel : item.yLabel
              );

            if (!b) {
              return "".concat(label, " (NaN)");
            }

            if (hoveredOutlierIndex >= 0) {
              var outlier = b.outliers[hoveredOutlierIndex];
              return ""
                .concat(label, " (outlier: ")
                .concat(toFixed.call(this, outlier), ")");
            }

            return ""
              .concat(label, " (min: $")
              .concat(toFixed.call(this, b.min), ", q1: $")
              .concat(toFixed.call(this, b.q1), ", median: $")
              .concat(toFixed.call(this, b.median), ", q3: $")
              .concat(toFixed.call(this, b.q3), ", max: $")
              .concat(toFixed.call(this, b.max), ")");
          }
        }
      }
// remaining options

sgratzl / chartjs-chart-boxplot

Correct Tooltip modification technique #8