npm install multer --save

{
   "fieldname":"avatar",  #前端上传文件input的name
   "originalname":"Wx.php",  #本地文件名
   "encoding":"7bit",  #文件编码类型
   "mimetype":"text/php",  #文件类型
   "destination":"uploads/",  #上传根目录
   "filename":"1497286037422Wx.php",  #上传后文件名
   "path":"uploads/1497286037422Wx.php",  #文件路径
   "size":18174  #文件大小
}

<form action="/test/upload" method="post" enctype="multipart/form-data">
  <input type="file" name="avatar">
  <input type="submit" name="提交">
</form>

// upload.js

var multer = require('multer');  # 引入模块

var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'uploads/')
  },
  filename: function (req, file, cb) {
    cb(null, Date.now()+file.originalname)
  }
})

var upload = multer({ storage: storage })

module.exports = upload;

destination  # 设置文件上传路径
filename    # 重命名文件

// file.js 

var express = require('express');
var router = express.Router();

// 引入配置文件
var upload = require('../config/upload');

router.post('/upload', upload.single('avatar'), function(req, res, next) {
  res.send(req.file);
});

module.exports = router;

upload.single(fname);  // 接收单文件
upload.array(fname[, maxCount])  //接收多文件，maxCount表示接收最大数量