const stage = new Konva.Stage({

  container: 'container',

  width: window.innerWidth,

  height: window.innerHeight

});

​

const layer = new Konva.Layer();

stage.add(layer);

​

const shape = new Konva.Circle({

  x: stage.width() / 2,

  y: stage.height() / 2,

  radius: 50,

  fill: 'green'

});

layer.add(shape);

​

const tr = new Konva.Transformer({

  nodes: [shape]

})

​

tr.update = function() {

  Konva.Transformer.prototype.update.call(tr);

  var rot = this.findOne('.rotater');

  rot.fill('orange');

}

​

tr.forceUpdate();

​

layer.add(tr);

​

​

layer.draw();

​

​

​