problem description

when uploading multiple files using formidable, there is always one more empty file, as shown in the following figure

so the traversal file stream is printed out, and sure enough, it is looped three times, and the code is as follows:

related codes

var form = new formidable.IncomingForm();
form.uploadDir = "public" + AVATAR_UPLOAD_FOLDER;     //
form.keepExtensions = true;     //
form.maxFieldsSize = 2 * 1024 * 1024;   //
var newPath;
var allFile=[];
form.on("file", function (filed, file) {
    console.log("filed:::",filed);
    console.log("file:::",file);
    allFile.push([filed, file]);//
    // console.log("**********=>allFile:",allFile);
}).parse(req, function (err, fields, files) {

    var extName = "";  //
    if(files.file && files.file.length>0){
        console.log("0");
        switch (files.file.type) {
            case "image/pjpeg":
                extName = "jpg";
                break;
            case "image/jpeg":
                extName = "jpg";
                break;
            case "image/png":
                extName = "png";
                break;
            case "image/x-png":
                extName = "png";
                break;
        }
        if (extName.length == 0) {
            res.locals.error = "pngjpg";
            res.render("index", {title: TITLE});
            return;
        }

        allFile.forEach(function(file,index){
            var fieldName=file[0];
            var types = file[1].name.split(".");
            var date = new Date();
            var ms = Date.parse(date);
            fs.renameSync(file[1].path,form.uploadDir+"/"+types[0]+"."+String(types[types.length-1]));//
        });
    }
    })
    
    

the following is the printout:

filed::: file
file::: File {
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  size: 0,
  path: "public\\avatar\\upload_255fc288f22bda9c2e6f3f985c353609",
  name: "",
  type: "application/octet-stream",
  hash: null,
  lastModifiedDate: null,
  _writeStream:
   WriteStream {
     _writableState:
      WritableState {
        objectMode: false,
        highWaterMark: 16384,
        finalCalled: true,
        needDrain: false,
        ending: true,
        ended: true,
        finished: true,
        destroyed: true,
        decodeStrings: true,
        defaultEncoding: "utf8",
        length: 0,
        writing: false,
        corked: 0,
        sync: true,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
        writecb: null,
        writelen: 0,
        bufferedRequest: null,
        lastBufferedRequest: null,
        pendingcb: 0,
        prefinished: true,
        errorEmitted: false,
        emitClose: false,
        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: false,
     _events: { open: [Function] },
     _eventsCount: 1,
     _maxListeners: undefined,
     path: "public\\avatar\\upload_255fc288f22bda9c2e6f3f985c353609",
     fd: null,
     flags: "w",
     mode: 438,
     start: undefined,
     autoClose: true,
     pos: undefined,
     bytesWritten: 0,
     closed: false } }
    filed::: file
    file::: File {
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  size: 16144,
  path:
   "public\\avatar\\upload_5427e66c7f095253103cf435ca326903.png",
  name: "1506492549107.png",
  type: "image/png",
  hash: null,
  lastModifiedDate: 2018-09-06T07:32:45.571Z,
  _writeStream:
   WriteStream {
     _writableState:
      WritableState {
        objectMode: false,
        highWaterMark: 16384,
        finalCalled: true,
        needDrain: false,
        ending: true,
        ended: true,
        finished: true,
        destroyed: true,
        decodeStrings: true,
        defaultEncoding: "utf8",
        length: 0,
        writing: false,
        corked: 0,
        sync: false,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
        writecb: null,
        writelen: 0,
        bufferedRequest: null,
        lastBufferedRequest: null,
        pendingcb: 0,
        prefinished: true,
        errorEmitted: false,
        emitClose: false,
        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: false,
     _events: {},
     _eventsCount: 0,
     _maxListeners: undefined,
     path:
      "public\\avatar\\upload_5427e66c7f095253103cf435ca326903.png",
     fd: null,
     flags: "w",
     mode: 438,
     start: undefined,
     autoClose: true,
     pos: undefined,
     bytesWritten: 16144,
     closed: false } }
filed::: file
file::: File {
  _events: {},
  _eventsCount: 0,
  _maxListeners: undefined,
  size: 18898,
  path:
   "public\\avatar\\upload_75052b6e88a8a2a04c3e98090b577dfd.png",
  name: "1506492173800.png",
  type: "image/png",
  hash: null,
  lastModifiedDate: 2018-09-06T07:32:45.575Z,
  _writeStream:
   WriteStream {
     _writableState:
      WritableState {
        objectMode: false,
        highWaterMark: 16384,
        finalCalled: true,
        needDrain: true,
        ending: true,
        ended: true,
        finished: true,
        destroyed: true,
        decodeStrings: true,
        defaultEncoding: "utf8",
        length: 0,
        writing: false,
        corked: 0,
        sync: false,
        bufferProcessing: false,
        onwrite: [Function: bound onwrite],
        writecb: null,
        writelen: 0,
        bufferedRequest: null,
        lastBufferedRequest: null,
        pendingcb: 0,
        prefinished: true,
        errorEmitted: false,
        emitClose: false,
        bufferedRequestCount: 0,
        corkedRequestsFree: [Object] },
     writable: false,
     _events: {},
     _eventsCount: 0,
     _maxListeners: undefined,
     path:
      "public\\avatar\\upload_75052b6e88a8a2a04c3e98090b577dfd.png",
     fd: null,
     flags: "w",
     mode: 438,
     start: undefined,
     autoClose: true,
     pos: undefined,
     bytesWritten: 18898,
     closed: false } }