= this.config[key]\n        }\n      }\n    }\n\n    return config\n  }\n\n  _cleanTipClass() {\n    const $tip = $(this.getTipElement())\n    const tabClass = $tip.attr('class').match(BSCLS_PREFIX_REGEX)\n    if (tabClass !== null && tabClass.length) {\n      $tip.removeClass(tabClass.join(''))\n    }\n  }\n\n  _handlePopperPlacementChange(popperData) {\n    this.tip = popperData.instance.popper\n    this._cleanTipClass()\n    this.addAttachmentClass(this._getAttachment(popperData.placement))\n ...