code: function normalizeArrowKey(event) {
    const {key, keyCode} = event
    /* istanbul ignore next (ie) */
    if (keyCode >= 37 && keyCode <= 40 && key.indexOf('Arrow') !== 0) {
      return `Arrow${key}`
    }
    return key
  }
docs: Normalizes the 'key' property of a KeyboardEvent in IE/Edge
  @param {Object} event a keyboardEvent object
  @return {String} keyboard key