TypeError: Cannot read property 'element' of undefined with busboy in node.js

Question

I am trying to upload a file to aws s3, I find the error:

TypeError: Can not read property 'element2' of undefined

I have tried to modify the variables, but the error continues, when I change req.file.element2 by req.body.element2 the error stops appearing, but it does not upload the file I want, even though I have tried to fix it it keeps appearing and I definitely do not know what to do, here is the code where my service is running:

   const Busboy = require('busboy');
   const AWS = require('aws-sdk');

   const BUCKET_NAME = 'hipopo-test';
   const IAM_USER_KEY = 'ASDASD5ASDDFGDFG6DFG';
   const IAM_USER_SECRET = 'y6838348FSD4SF21f31333gR232ER432f3423';

   module.exports = (app) => {


   app.post('/api/upload', function (req, res, next) {

   const element1 = req.body.element1;

   var busboy = new Busboy({ headers: req.headers });

  busboy.on('file', function(fieldname, file, filename, encoding, 
  mimetype) {
  console.log('File [' + fieldname + ']: filename: ' + filename);
      file.on('data', function(data) {
      console.log('File [' + fieldname + '] got ' + data.length + ' 
      bytes');
   });
 });


   busboy.on('finish', function() {
   console.log('Upload finished');
   });


   const file = req.file.element2;
   console.log(file);

   function uploadToS3(file) {
     let s3bucket = new AWS.S3({
       accessKeyId: IAM_USER_KEY,
       secretAccessKey: IAM_USER_SECRET,
       Bucket: BUCKET_NAME
     });
     s3bucket.createBucket(function () {

         var params = {
           Bucket: BUCKET_NAME,
           Key: file.name,
           Body: file.data
         };
         s3bucket.upload(params, function (err, data) {
           if (err) {
             console.log('error in callback');
             console.log(err);
           }
           console.log('success');
           console.log(data);
         });
     });

     uploadToS3(file);
   };

  req.pipe(busboy);
 });
}