error when choosing file with input

[khallad]

when uploading only 1 file (with input) it doesn't work, but with multiple files it works fine. how can I fix that

document.querySelector('#pictures').addEventListener('change', (e) => {

  const formData = extractFormData('#statusForm');
  while (fileCollection.length) {
    fileCollection.pop();
    console.log("test");

  }
  [].slice.call(formData.pictures).map(f => fileCollection.push(f));
  console.log(formData.pictures);

      
});
document.forms.statusForm.addEventListener('submit', (e) => {
  e.preventDefault();
  e.stopPropagation();

  const formData = extractFormData('#statusForm');
  const text = formData.status;
  formData.status = '';
  sendData(text, fileCollection)
  setTimeout(() => {
    while (fileCollection.length) {
      fileCollection.pop();
    }
  }, 100);
});

var extractFormData = function (form) {
  const formData = new FormData(document.querySelector(form));
  values = {};
  for(var pair of formData.entries()) {
    if( values[pair[0]] ) {
      if(!(values[pair[0]] instanceof Array)) {
        values[pair[0]] = new Array(values[pair[0]]);

      }
      values[pair[0]].push(pair[1]);


    } else {

      values[pair[0]] = pair[1];
    
    }
  }

  return values;
}