Prevent Hover state save

I want to prevent save to json the state of the over

by STHayden

HTML

<script src="htts://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.6.6/fabric.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.6.6/fabric.min.js"></script>
<canvas id="canvas"></canvas>

JavaScript

var canvas = new fabric.Canvas('canvas', {
  perPixelTargetFind: true
});

canvas.on("mouse:down", function(event) {
  var state = canvas.toJSON();
  state.objects.forEach(o => {
    if (o.trueColor) {
      o.fill = o.trueColor;
      delete o.trueColor;
    }
  })
  console.log(state);
});
//click on the rect to see that the color red is saved in the json
//shown in the console log, but i want the original State, the red fill
canvas.on("mouse:over", function(event) {
  if ("target" in event) {
    color = event.target.fill;
    event.target.fill = "red";
    event.target.trueColor = color;
    canvas.renderAll();
  }
});
canvas.on("mouse:out", function(event) {
  if ("target" in event) {
    event.target.fill = event.target.trueColor;
    canvas.renderAll();
  }
});

var rect = new fabric.Rect({
  left: 100,
  top: 100,
  fill: 'blue',
  width: 20,
  height: 20,
  angle: 45
});
canvas.add(rect);