Javascript 如何在 Chart.js v2 中使用两个 Y 轴？

How to use two Y axes in Chart.js v2?

提问by just.me

I am trying to create a line chart with two datasets, each with its own Y scale / axis (one to the left, one to the right of the graph) using Chart.js.

我正在尝试使用 Chart.js 创建一个包含两个数据集的折线图，每个数据集都有自己的 Y 比例尺/轴（一个在图表的左侧，一个在图表的右侧）。

This is my code (jsfiddle):

这是我的代码（jsfiddle）：

var canvas = document.getElementById('chart');
new Chart(canvas, {
  type: 'line',
  data: {
    labels: [ '1', '2', '3', '4', '5' ],
    datasets: [
      {
        label: 'A',
        yAxesGroup: 'A',
        data: [ 100, 96, 84, 76, 69 ]
      },
      {
        label: 'B',
        yAxesGroup: 'B',
        data: [ 1, 1, 1, 1, 0 ]
      }
    ]
  },
  options: {
    yAxes: [
      {
        name: 'A',
        type: 'linear',
        position: 'left',
        scalePositionLeft: true
      },
      {
        name: 'B',
        type: 'linear',
        position: 'right',
        scalePositionLeft: false,
        min: 0,
        max: 1
      }
    ]
  }
});

However, the second axis is not visible and the second dataset is still scaled exactly as the first (0 to 100 instead of 0 to 1). What do I need to change?

但是，第二个轴不可见，第二个数据集仍与第一个数据集完全相同（0 到 100，而不是 0 到 1）。我需要改变什么？

回答by Quince

For ChartJs 2.x only a couple changes need to be made (it looks like you have tried to combine 2.x options with the multi-axes options from my fork?),

对于 ChartJs 2.x，只需要进行一些更改（看起来您已经尝试将 2.x 选项与我的 fork 中的多轴选项结合起来？），

• The yAxesfield needs to be in a scalesobject
• the yAxis is referenced by id not name.
• For the scale steps/size you just need to wrap these options in a ticksobject.
• No need forscalePositionLeftthis is covered by position

• 该yAxes字段需要在一个scales对象中
• yAxis 由 id 而不是名称引用。
• 对于缩放步长/大小，您只需要将这些选项包装在一个ticks对象中。
• 不需要scalePositionLeft这被涵盖position

Example:

例子：

var canvas = document.getElementById('chart');
new Chart(canvas, {
  type: 'line',
  data: {
    labels: ['1', '2', '3', '4', '5'],
    datasets: [{
      label: 'A',
      yAxisID: 'A',
      data: [100, 96, 84, 76, 69]
    }, {
      label: 'B',
      yAxisID: 'B',
      data: [1, 1, 1, 1, 0]
    }]
  },
  options: {
    scales: {
      yAxes: [{
        id: 'A',
        type: 'linear',
        position: 'left',
      }, {
        id: 'B',
        type: 'linear',
        position: 'right',
        ticks: {
          max: 1,
          min: 0
        }
      }]
    }
  }
});

fiddle example

小提琴示例