javascript - chart.js load totally new data

Question

The API for chart.js allows one to edit points of the datasets loaded into it, for example:

.update( )

Calling update() on your Chart instance will re-render the chart with any updated values, allowing you to edit the value of multiple existing points, then render those in one animated render loop.

.addData( valuesArray, label )

Calling addData(valuesArray, label) on your Chart instance passing an array of values for each dataset, along with a label for those points.

.removeData( )

Calling removeData() on your Chart instance will remove the first value for all datasets on the chart.

All of these are great, but I cannot figure out how to load an entirely new dataset in, wiping out the old. The documentation does not seem to cover this.

Answer 1

I had huge problems with this

First I tried .clear() then I tried .destroy() and I tried setting my chart reference to null

What finally fixed the issue for me: deleting the <canvas> element and then reappending a new <canvas> to the parent container

---

There's a million ways to do this:

var resetCanvas = function () {
  $('#results-graph').remove(); // this is my <canvas> element
  $('#graph-container').append('<canvas id="results-graph"><canvas>');
  canvas = document.querySelector('#results-graph'); // why use jQuery?
  ctx = canvas.getContext('2d');
  ctx.canvas.width = $('#graph').width(); // resize to parent width
  ctx.canvas.height = $('#graph').height(); // resize to parent height

  var x = canvas.width/2;
  var y = canvas.height/2;
  ctx.font = '10pt Verdana';
  ctx.textAlign = 'center';
  ctx.fillText('This text is centered on the canvas', x, y);
};