TinyMCE file_picker_callback从默认浏览器文件选择中选择文件

I am using TinyMCE in a project and want the user to select and upload file to the server using its default Insert/Edit Link window

The following code works fine for images but I am not sure how can this be handled in case of inserting a file for the link.

tinymce.init({
selector: "#uploadElementDiv",
plugins: [
    "link image"
],
toolbar: "link unlink image",
image_advtab: true,
file_picker_types: 'file image',
file_picker_callback: function(callback, value, meta) {
  if (meta.filetype == 'image') {
    $('#upload').trigger('click');
    $('#upload').on('change', function() {
      var file = this.files[0];
      var reader = new FileReader();
      reader.onload = function(e) {
        callback(e.target.result, {
          alt: ''
        });
      };
      reader.readAsDataURL(file);
    });
  }
  if (meta.filetype == 'file') {
  //some code here
  }
}

}

 <iframe id="uploadElementDiv" contenteditable="true" style="width:100%;border:none;height:100%;margin-top:10px;" ></iframe>
   <input name="image" type="file" id="upload" class="hidden" onchange="">