ChartJS:在工具提示中显示混合图表的所有标签

var chartData = {
  labels: ['标签1', '标签2', '标签3', '标签4', '标签5'],
  datasets: [
    {
      type: 'line',
      label: '折线图',
      data: [10, 20, 30, 40, 50],
      borderColor: 'red',
      fill: false
    },
    {
      type: 'bar',
      label: '柱状图',
      data: [50, 40, 30, 20, 10],
      backgroundColor: 'blue'
    }
  ]
};

var chartOptions = {
  tooltips: {
    callbacks: {
      label: function(tooltipItem, data) {
        var datasetLabel = data.datasets[tooltipItem.datasetIndex].label || '';
        var label = data.labels[tooltipItem.index];
        var value = data.datasets[tooltipItem.datasetIndex].data[tooltipItem.index];
        return datasetLabel + ': ' + label + ' - ' + value;
      }
    }
  }
};

var chart = new Chart(document.getElementById('chart'), {
  type: 'bar',
  data: chartData,
  options: chartOptions
});