新增后端带条件导出功能（示例见用户管理控制器）

src/utils/index.js

@@ -147,3 +147,15 @@ export function removeClass(ele, cls) {
     ele.className = ele.className.replace(reg, ' ')
   }
 }
+
+export function downloadFile(obj, name, suffix) {
+  const url = window.URL.createObjectURL(new Blob([obj]))
+  const link = document.createElement('a')
+  link.style.display = 'none'
+  link.href = url
+  const fileName = parseTime(new Date()) + '-' + name + '.' + suffix
+  link.setAttribute('download', fileName)
+  document.body.appendChild(link)
+  link.click()
+  document.body.removeChild(link)
+}