node 接收前端上传的 form-data 文件流

插件： multiparty

用法：

const multiparty = require('multiparty')
const path = require('path')
const form_data = new multiparty.Form({
  uploadDir: path.resolve(__dirname, '../../uploads')
})

router.post('/upload', (req, res) => {
  form_data.parse(req, function (err, fields, files) {
    console.log(err, fields, files)
  })
})