resize(options) {
    const newWidth = isNumber(options.width) ? `${options.width}px` : `${options.width}`
    const newHeight = isNumber(options.height) ? `${options.height}px` : `${options.height}`
    this.el.style.width = newWidth
    this.el.style.height = newHeight
    this.onResize(options)
    return this
  }
resize current element
@method resize
@param {Object} options the options object
@return {UIObject} itself