I have to try to create some test usen js Composition, I'm following this article: https://www.koderhq.com/tutorial/javascript/composition/#what-is

I have a js class

class FileField {

  constructor () {

  }
  /**
   * Upload file to file field.
   *
   * @param {string} InputAttribute
   * @param {string} url
   * @param {string} AltAttribute
   */
  uploadField(InputAttribute, url, AltAttribute ) {}
}
export default {FileField}

And I try to use this class in this way in another class:

import { DefaultContent } from "./DefaultContent/DefaultContent";
import { PROPERTY } from "./DefaultContent/DefaultContent";
import { FileField } from "./DefaultContent/FileField";

export default class ArticlePage extends DefaultContent {
  constructor(FileField) {
    this.fileField = new FileField();
  }

  fillImageField() {

    // Upload the file
    this.fileField.uploadFile(
      this.imageInput,
      "/node/add/article?element_parents=field_image/widget/0&ajax_form=1&_wrapper_format=drupal_ajax",
      this.imageAltDescription,
      );
   }
}

I get the error: > FileField is not a constructor

I have checked articles and StackOverflow questions but none works with my code.

Thanks.