nodejs使用中间件multer实现多文件上传，为什么还是只能一次上传一个文件呢？无法多选

const express = require("express");
const path = require("path");
const hash = require("object-hash");
const sd = require("silly-datetime");
const mkdirp = require("mkdirp");
var multer = require("multer");
// var upload = multer({ dest: "static/uploads" });
var storage = multer.diskStorage({
  destination: async function (req, file, cb) {
    //1.获取当前日期
    let day = sd.format(new Date(), "YYYYMMDD");
    let dir = path.join("static/uploads", day);
    //2.按照日期生成存储目录
    await mkdirp(dir);
    cb(null, dir);
  },
  filename: function (req, file, cb) {
    let extname = path.extname(file.originalname);
    cb(null, hash(file.originalname) + extname);
    // cb(null, file.originalname.split(".")[0] + Date.now() + extname);
  },
});
var upload = multer({ storage });

var router = express.Router();
router.get("/add", (req, res) => {
  res.render("admin/user/add");
});

router.post("/doAdd", upload.array("pic1", 3), (req, res) => {
  res.send({
    body: req.body,
    files: req.files,
  });
});

后端代码

 <form
      action="/admin/user/doAdd"
      method="post"
      enctype="multipart/form-data"
    >
      <input type="text" name="title" id="title" /><br /><br />
      图片1 <input type="file" name="pic1" id="pic1" /><br /><br />
      <!-- 图片2 <input type="file" name="pic2" id="pic2" /><br /><br /> -->
      <textarea name="desc" id="desc" cols="30" rows="10"></textarea
      ><br /><br />
      <input type="submit" value="提交" />
    </form>

后端渲染

页面

<input type="file" name="pic1" id="pic1" /> 这个元素加个属性 multiple

如 <input type="file" multiple="multiple" />