class DragAndDropHandler {

  get _isDragAndDropHandler() {
    return true
  }

  dragStart(params, context) { // eslint-disable-line
    // nothing
  }

  drop(params, context) { // eslint-disable-line
    // nothing
  }

  dragEnd(params, context) { // eslint-disable-line
    // nothing
  }

}

DragAndDropHandler.prototype._isDragAndDropHandler = true

export default DragAndDropHandler

class DragAndDropHandler {

  get _isDragAndDropHandler() {
    return true
  }

  dragStart(params, context) { // eslint-disable-line
    // nothing
  }

  drop(params, context) { // eslint-disable-line
    // nothing
  }

  dragEnd(params, context) { // eslint-disable-line
    // nothing
  }

}

export default DragAndDropHandler

Use only property getter for _isDragAndDropHandler.