vue el-upload实现多文件上传

代码：

<el-upload
          :auto-upload="false"
          multiple
          class="upload-demo"
          action="#"
          :on-change="uploadChange"
          :before-upload="handleBeforeUpload"
          :before-remove="beforeRemove"
          :on-remove="upLoadRemove"
          :on-preview="downLoadFile"
          :file-list="fileList"
        >
          <el-button size="small" icon="el-icon-plus" slot="trigger"
            >选取文件</el-button
          >
          <el-button
            style="margin-left: 10px"
            size="small"
            icon="el-icon-upload"
            type="success"
            @click="submitUpload"
            :disabled="fileList.length <= 0"
            >上传到服务器</el-button
          >
          <div class="el-upload__tip" slot="tip">仅限doc和docx文件</div>
        </el-upload>

 // 多文件上传
    fileUpload() {
      this.fileList = [];
      this.filedialogVisible = true;
    },
    // 上传前
    handleBeforeUpload(file) {
      console.log(file);
      // 校验
      let legalName = ["doc", "docx"];
      // 拿到后缀名
      let name = file.name.substring(
        file.name.lastIndexOf(".") + 1,
        file.name.length
      );
      if (legalName.includes(name)) {
        // console.log(legalName.includes(name));
      } else {
        this.$message.info("文件格式不对，仅限doc和docx");
        return false;
      }
    },

    // 拖拽上传
    beforeRemove(file, fileList) {
      this.fileList = fileList;
      // return this.$confirm(`确定移除 ${file.name}？`);
    },
    // 移除附件
    upLoadRemove(file, fileList) {
      let tempFileList = [];
      for (var index = 0; index < this.fileList.length; index++) {
        if (this.fileList[index].name !== file.name) {
          tempFileList.push(this.fileList[index]);
        }
      }
      this.fileList = tempFileList;
    },
    // 监控上传文件列l表
    uploadChange(file, fileList) {
      let existFile = fileList
        .slice(0, fileList.length - 1)
        .find((f) => f.name === file.name);
      if (existFile) {
        this.$message.error("当前文件已经存在!");
        fileList.pop();
      }
      this.fileList = fileList;
      // 校验
      let legalName = ["doc", "docx"];
      // 拿到后缀名
      let name = file.name.substring(
        file.name.lastIndexOf(".") + 1,
        file.name.length
      );
      if (legalName.includes(name)) {
        console.log(legalName.includes(name));
      } else {
        this.$message.info("文件格式不对，仅限doc和docx");
        return false;
      }
    },
    // 上传到服务器  formidable接收
    async submitUpload() {
      let formData = new FormData();
      this.fileList.forEach((item) => {
        formData.append("files", item.raw);
      });
      formData.append("parentId", this.allId);
      // append追加后console.log后仍为空,需要用formData.get("键")的方法获取值
      const res = await fileUpload(formData);
      console.log(res);
      if (res.status != 200) {
        return this.$message.error("上传失败");
      }
      this.$message.success("上传成功");
      this.fileBox(this.allId);
      this.filedialogVisible = false;
    },
    // 点击文件进行下载
    downLoadFile(file) {
      var a = document.createElement("a");
      var event = new MouseEvent("click");
      a.download = file.name;
      a.href = file.url;
      a.dispatchEvent(event);
    },
    //  :on-exceed="handleExceed"
    // 选取文件超过数量提示
    // handleExceed(files, fileList) {
    //   this.$message.warning(`当前限制选择 5 个文件，本次选择了 ${files.length} 个文件，共选择了 ${files.length + fileList.length} 个文件`);
    // },