Reactで使っていたchart.jsをv2.7からv3.9にアップデートする

const options = {
  plugins: {
    tooltip: {
      callbacks: {
        label: function(tooltipItem: TooltipItem<'pie'>): string | string[] {
          const label = tooltipItem.label;
          const value = tooltipItem.dataset.data[tooltipItem.dataIndex] as number;

          return `${label}: ${value}`;
        }
      }
    }
  }
}

Chart.overrides["pie"].plugins.tooltip.callbacks.label = function(tooltipItem: TooltipItem<"pie">): string | string[] {
  console.log("called tooltip label callbacks");
  const label = tooltipItem.label;
  const value = tooltipItem.dataset.data[tooltipItem.dataIndex] as number;

  return `${label}: ${value}`;
}

import { ArcElement, Chart, Legend, PieController, Tooltip } from "chart.js";

Chart.register(PieController, ArcElement, Legend);