ng2- chart :如何在图表中显示百分比值？

import { Component } from '@angular/core';

@Component({
  selector: 'app-chart',
  template: `
    <div>
      <canvas baseChart
              [data]="chartData"
              [options]="chartOptions"
              [plugins]="chartPlugins"
              [legend]="chartLegend"
              [chartType]="chartType"></canvas>
    </div>
  `
})
export class ChartComponent {
  chartData = {
    labels: ['Red', 'Blue', 'Yellow'],
    datasets: [
      {
        data: [300, 50, 100],
        backgroundColor: ['#FF6384', '#36A2EB', '#FFCE56'],
        hoverBackgroundColor: ['#FF6384', '#36A2EB', '#FFCE56']
      }
    ]
  };

  chartOptions = {
    tooltips: {
      callbacks: {
        label: (tooltipItem, data) => {
          const dataset = data.datasets[tooltipItem.datasetIndex];
          const total = dataset.data.reduce((previousValue, currentValue) => previousValue + currentValue);
          const currentValue = dataset.data[tooltipItem.index];
          const percentage = Math.floor((currentValue / total) * 100 + 0.5);
          return percentage + '%';
        }
      }
    }
  };

  chartPlugins = [];

  chartLegend = true;

  chartType = 'doughnut';
}