导出，后台接口直接返回导出内容

let url = baseURL + 'task/expor?id=' + obj.id
        let link = document.createElement('a')
        link.style.display = 'none'
        link.setAttribute('href', url)
        link.click()

根据后台接口修改接口地址即可，前提：后台那边导出测试通过