文件上传并添加限制

<el-upload
   class="avatar-uploader"
   action="1"
   :show-file-list="false"
   accept="/xlsx"
   :before-upload="(file)=>{ return beforeAvatarUpload(file,null)}">
   <el-button type="primary">点击上传</el-button>
</el-upload>

beforeAvatarUpload(file,index) {
        //上传之前事件
        let that = this;
        let type1 = file.name.split('.');  //获取文件后缀
        let type2 = type1[type1.length - 1].toLowerCase();
        let type ="xlsx,xls,csv,pdf",
            isType = type.indexOf(type2);

        if(isType < 0){
            this.$message.error(`请上传xlsx,xls,csv,pdf格式的文件!，您的文件格式为 ${type2}`);
            return;
        }
        console.log(type2);

        let isLt2M = file.size / 1024 / 1024 < 5;
        if (!isLt2M) {
            this.$message.error('上传文件大小不能超过 5MB!');
            return isLt2M;
        }
        let fd = new FormData();
        fd.append("file",file);
        inputObj(fd).then(res=>{
            if(res.data.resp_code == 200){
                this.$message.success('上传成功！');
            }else{
                this.$message.error('上传失败！');
            }
        })
      },