如何將所有值的總和添加為 Chart.Js 中圓環圖的圖表標題？

Question

我的示例目前如下所示：

var ctx = document.getElementById("myChart");
var myChart = new Chart(ctx, {
    type: 'doughnut',
    data: {
        labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
        datasets: [{
            label: '# of Votes',
            data: [12, 19, 3, 5, 2, 3],
            backgroundColor: [
                'rgba(255, 99, 132, 0.2)',
                'rgba(54, 162, 235, 0.2)',
                'rgba(255, 206, 86, 0.2)',
                'rgba(75, 192, 192, 0.2)',
                'rgba(153, 102, 255, 0.2)',
                'rgba(255, 159, 64, 0.2)'
            ],
            borderColor: [
                'rgba(255,99,132,1)',
                'rgba(54, 162, 235, 1)',
                'rgba(255, 206, 86, 1)',
                'rgba(75, 192, 192, 1)',
                'rgba(153, 102, 255, 1)',
                'rgba(255, 159, 64, 1)'
            ],
            borderWidth: 1
        }]
    },
    options: {
        rotation: 1 * Math.PI,
        circumference: 1 * Math.PI,
        title: {
           display: true,
           text: 'Custom Chart Title',
           position: 'bottom'
        }
     }
});

現在我想顯示data: [12, 19, 3, 5, 2, 3]值的總和data: [12, 19, 3, 5, 2, 3]作為圖表的標題（因此，在這種情況下，標題將為 44）。 一些示例小提琴在這里： https : //jsfiddle.net/ktq8​​mb0z/ 。 我怎樣才能在 Chart.Js 中實現這一點？

Answer 1

您可以用戶減少功能

dataset[0].data.reduce((x,y)=>x+y)

或者您也可以使用它

dataset.reduce((t,d) => t + d.data.reduce((a,b) => a+b),0)

 var ctx = document.getElementById("myChart"); var dataset=[{ label: '# of Votes', data: [12, 19, 3, 5, 2, 3], backgroundColor: [ 'rgba(255, 99, 132, 0.2)', 'rgba(54, 162, 235, 0.2)', 'rgba(255, 206, 86, 0.2)', 'rgba(75, 192, 192, 0.2)', 'rgba(153, 102, 255, 0.2)', 'rgba(255, 159, 64, 0.2)' ], borderColor: [ 'rgba(255,99,132,1)', 'rgba(54, 162, 235, 1)', 'rgba(255, 206, 86, 1)', 'rgba(75, 192, 192, 1)', 'rgba(153, 102, 255, 1)', 'rgba(255, 159, 64, 1)' ], borderWidth: 1 }]; var myChart = new Chart(ctx, { type: 'doughnut', data: { labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"], datasets: dataset }, options: { rotation: 1 * Math.PI, circumference: 1 * Math.PI, title: { display: true, text: 'Custom Chart Title and Sum is : '+dataset.reduce((t,d) => t + d.data.reduce((a,b) => a+b),0), position: 'bottom' } } }); 

 .snippet-code .snippet-result .snippet-result-code{ min-height:640px!important; height:640px!important; } 

 <script src="https://cdn.jsdelivr.net/npm/chart.js@2.8.0"></script> <canvas id="myChart" width="400" height="400"></canvas> 

Answer 2

從 ChartJS 3.xx 版開始：

• 半甜甜圈配置了度數
• 標題是“插件”的一部分

因此，使用此配置：

options: {
  rotation: -90,
  circumference: 180,
    plugins: {
      title: {
        display: true,
        text: 'Total: ' + data.reduce((total, dataPoint) => total + dataPoint, 0),
        position: 'bottom',
      },
    },
}