导出文件

const getExport = (data, fileName) => {

  const blob = new Blob([data])

  // let fileName = this.exportTitle;

  if ('download' in document.createElement('a')) {

      // 非IE下载

      const elink = document.createElement('a')

      elink.download = fileName

      elink.style.display = 'none'

      elink.href = URL.createObjectURL(blob)

      document.body.appendChild(elink)

      elink.click()

      URL.revokeObjectURL(elink.href)

      document.body.removeChild(elink)

  } else {

      // IE10+下载

      navigator.msSaveBlob(blob, fileName)

  }

}