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how to properly implement crosshair plugin with vue chartjs? - keep getting Cannot read properties of undefined error (reading 'dragStarted')

I'm struggling with setting chartjs-plugin-crosshair to work with my chart (chartjs).

Project dependencies are:

  • vue-chartjs: 4.1.0
  • chartjs-plugin-crosshair: 1.2.0
  • chart.js: 3.7.1

i'm getting errors:

first: Uncaught TypeError: Cannot read properties of undefined (reading 'dragStarted')

then (on mouse move over chart): Uncaught TypeError: Cannot read properties of undefined (reading 'length')

My component:

<template>
      <Line :chart-data="chartData" :plugins="[CrosshairPlugin]" :chart-options="chartOptions" ref="myChart" />
</template

<script setup>
import { Line } from 'vue-chartjs'
import { Chart as ChartJS, Title, Tooltip, Legend, PointElement, LineElement, CategoryScale, LinearScale, TimeSeriesScale } from 'chart.js'
import {CrosshairPlugin,Interpolate} from 'chartjs-plugin-crosshair';

ChartJS.register(Title, Tooltip, Legend, PointElement, LineElement, CategoryScale, LinearScale, TimeSeriesScale)

const myChart = ref();

const chartData ={
  labels: [1,2,3,4],
  datasets: [{label:'test', data:[51,52,53,54],borderWidth:1, borderColor:'#f0f'}]
}

const chartOptions = {
   interaction: {
        mode: 'nearest'
   },
   scales: {
       xAxes: {
           stacked:true,
           grid: {
               color:"rgba(80,201,209,.3)",
               borderColor:"rgba(80,201,209,1)"
           },
           title: {
               display:true,
               text: 'value'
           },
           ticks: {
               color:"rgba(80,201,209,1)"
               source: 'labels',
           },
       },
       yAxes: {
           grid: {
               color:"rgba(80,201,209,.3)",
               borderColor:"rgba(80,201,209,1)"
           },
           title: {
               display: false,
           },
           ticks: {
               color:rgba(80,201,209,1),
           },
       },
   },
   plugins: {
        crosshair:
           {
                sync: {
                    enabled: false
                },
                zoom: {
                    enabled: false
                },
                snap:  {
                    enabled: true
                }
           }
   }
}

can anyone help?

Solution

  • This is because you gave your scales a custom ID, setting them back to the default x and y (by changing the object keys from yAxes to y and from xAxes to x) will resolve your issue:

    const options = {
  type: 'line',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        borderColor: 'pink'
      },
      {
        label: '# of Points',
        data: [7, 11, 5, 8, 3, 7],
        borderColor: 'orange'
      }
    ]
  },
  options: {
    hover: {
      intersect: false
    },
    scales: {
      x: {
        stacked: true,
        grid: {
          color: "rgba(80,201,209,.3)",
          borderColor: "rgba(80,201,209,1)"
        },
        title: {
          display: true,
          text: 'value'
        },
        ticks: {
          color: "rgba(80,201,209,1)",
          source: 'labels',
        },
      },
      y: {
        grid: {
          color: "rgba(80,201,209,.3)",
          borderColor: "rgba(80,201,209,1)"
        },
        title: {
          display: false,
        },
        ticks: {
          color: 'rgba(80, 201, 209, 1)',
        },
      },
    },
    plugins: {
      crosshair: {
        sync: {
          enabled: false
        },
        zoom: {
          enabled: false
        },
        snap: {
          enabled: true
        }
      }
    }
  }
}

const ctx = document.getElementById('chartJSContainer').getContext('2d');
new Chart(ctx, options);
    <body>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.8.0/chart.js"></script>
  <script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-crosshair"></script>
</body>