addClasses = (container, popup, params) => {
  dom.addClass(container, params.showClass.backdrop)
  if (params.animation) {
    // this workaround with opacity is needed for https://github.com/sweetalert2/sweetalert2/issues/2059
    popup.style.setProperty('opacity', '0', 'important')
    dom.show(popup, 'grid')
    setTimeout(() => {
      // Animate popup right after showing it
      dom.addClass(popup, params.showClass.popup)
      // and remove the opacity workaround
      popup.style.removeProperty('opacity')
    }, SHOW_CLASS_TIMEOUT) // 10ms in order to fix #2062
  } else {
    dom.show(popup, 'grid')
  }

  dom.addClass([document.documentElement, document.body], swalClasses.shown)
  if (params.heightAuto && params.backdrop && !params.toast) {
    dom.addClass([document.documentElement, document.body], swalClasses['height-auto'])
  }
}
@param {HTMLElement} container
@param {HTMLElement} popup
@param {SweetAlertOptions} params