Chart.js doesn't show anything

user_1437705 0
Viewed 65

I'm trying to periodically update a chart. The data is making into the dataset but I can't get it to draw the chart. What am I doing wrong?

const ctx = document.querySelector('#apichart canvas').getContext('2d');
const apichart = new Chart(ctx, {
  type: 'line',
  data: {datasets:[{
    label:'Pressure',
    data: [1025,1000],
    fill:false,
    borderColor: 'rgb(75, 192, 192)',
    tension:0.1
  }]},
  options: {
    scales: {
      y: {
        beginAtZero: true
      }
    }
  }
});

setInterval(function run(){
  apichart.data.datasets[0].data.push(1025 * Math.random());
  apichart.update();
}, 10000);
#apichart{background:#777; position:absolute; top:0; right:0; bottom:0; left:0;}
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.6.2/chart.min.js"></script>
<div id="apichart">
    <canvas></canvas>
</div>

chart.js javascript
1 Answers

I think this problem related to labels, so I have added labels array and update them in setInterval each time and it works.

const ctx = document.querySelector('#apichart canvas').getContext('2d');
const apichart = new Chart(ctx, {
  type: 'line',
  data: {labels: [1, 2],
datasets:[{
    label:'Pressure',
    data: [1025,1000],
    fill:false,
    borderColor: 'rgb(75, 192, 192)',
    tension:0.1
  }]},
  options: {
    scales: {
      y: {
        beginAtZero: true
      }
    }
  }
});

setInterval(function run(){
apichart.data.labels.push(Math.random());
  apichart.data.datasets[0].data.push(1025 * Math.random());
  apichart.update();
}, 1000);
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.6.2/chart.min.js"></script>
<div id="apichart">
    <canvas></canvas>
</div>

user_18611440
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