asset_zip(this.delarr).then((res) => {
    const content = res.data
    const blob = new Blob([content],{type:"application/zip"})
    var timestamp = (new Date()).valueOf();
    const fileName = timestamp+'.zip'
    if ('download' in document.createElement('a')) { // 非IE下载
        const elink = document.createElement('a')
        elink.download = fileName
        elink.style.display = 'none'
        elink.href = window.URL.createObjectURL(blob)
        document.body.appendChild(elink)
        elink.click()
        window.URL.revokeObjectURL(elink.href) // 释放URL 对象
        document.body.removeChild(elink)
    } else { // IE10+下载
        navigator.msSaveBlob(blob, fileName)
    }
})

不能用base64转成blob，不然会文件大小对里边没东西，下载其他类型修改type，