html

<form id="uploadImgForm" class="form-upload" action="/topic/uploadTopicImg" method="post" enctype="multipart/form-data">
            <legend>Upload topic image</legend>
            <label>topic image file</label><input name="uploadImg" placeholder="topic image file"  type="file"/>
            <button type="submit" class="btn btn-primary">Upload image</button>
        </form>

js

exports.uploadTopicImg = function(req,res,next){
   var file = req.files && req.files.uploadImg;
   if (!file) {
          res.send({ status: 'failed', message: 'no file' });
          return;
   }else{
          console.log("file name:"+file.name);
          console.log("file path:"+file.path);
   }

};