delete selected objects in fabricjs

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.19/fabric.min.js"></script>
<canvas id="paper" width="400" height="400" style="border:1px solid #ccc"></canvas>

JavaScript

var canvas = this.__canvas = new fabric.Canvas('paper',{
                preserveObjectStacking: true
            });
$(canvas.getElement().parentNode).on('DOMMouseScroll mousewheel', function(e) {
  var e = window.event || e; // old IE support
  var delta = Math.max(-1, Math.min(1, (e.wheelDelta || -e.originalEvent.detail)));
  if (delta > 0) {
    canvas.zoomToPoint({ x: canvas.width / 2, y: canvas.height / 2 }, canvas.getZoom() * 1.1);
  } else {
    canvas.zoomToPoint({ x: canvas.width / 2, y: canvas.height / 2 }, canvas.getZoom() / 1.1);
  }
  return false;
});
const data = {
    red:{
    	top: 50,
        left: 50,
        angle: 0,
        width: 300,
        height: 200
    },
	yellow:{
    	top: 50,
        left: 50,
        angle: 20,
        width: 100,
        height: 100
    }
};
const yellow = new fabric.Rect({
    left: data.yellow.left, 
    top:  data.yellow.top,
    fill: 'yellow',
    angle:  data.yellow.angle,
    width: data.yellow.width,
    height: data.yellow.height,
    originX: 'center',
    originY: 'center',
    opacity: .7
});

yellow.setPositionByOrigin({x:yellow.getLeft() + yellow.getWidth() / 2, y: yellow.getTop() + yellow.getHeight() / 2}, 'center', 'center');

fabric.Image.fromURL('//images.sftcdn.net/images/t_optimized,f_auto/p/85e6f558-9a68-11e6-bdf1-00163ed833e7/1312338326/slack-logo.png', function(img) {
    const patternSourceCanvas = new fabric.StaticCanvas();
    patternSourceCanvas.enableRetinaScaling = false;
    patternSourceCanvas.setBackgroundColor('red', patternSourceCanvas.renderAll.bind(patternSourceCanvas));
    patternSourceCanvas.setBackgroundImage(img, patternSourceCanvas.renderAll.bind(patternSourceCanvas), {
        top: yellow.getTop() - yellow.getWidth() / 2,
        left: yellow.getLeft() - yellow.getHeight() / 2,
        width: yellow.getWidth(),
        height: yellow.getHeight(),
        angle: yellow.getAngle(),
        scaleX: 1,
        scaleY: 1,
        originX: 'center',
        originY:...