React_Client_App_Access/node_modules/react-dropzone/examples/plugins

The hook accepts a getFilesFromEvent prop that enhances the handling of dropped file system objects and allows more flexible use of them e.g. passing a function that accepts drop event of a folder and resolves it to an array of files adds plug-in functionality of folders drag-and-drop.

Though, note that the provided getFilesFromEvent fn must return a Promise with a list of File objects (or DataTransferItem of {kind: 'file'} when data cannot be accessed). Otherwise, the results will be discarded and none of the drag events callbacks will be invoked.

In case you need to extend the File with some additional properties, you should use Object.defineProperty() so that the result will still pass through our filter:

import React from 'react';
import {useDropzone} from 'react-dropzone';

function Plugin(props) {
  const {acceptedFiles, getRootProps, getInputProps} = useDropzone({
    getFilesFromEvent: event => myCustomFileGetter(event)
  });

  const files = acceptedFiles.map(f => (
    <li key={f.name}>
      {f.name} has <strong>myProps</strong>: {f.myProp === true ? 'YES' : ''}
    </li>
  ));

  return (
    <section className="container">
      <div {...getRootProps({className: 'dropzone'})}>
        <input {...getInputProps()} />
        <p>Drag 'n' drop some files here, or click to select files</p>
      </div>
      <aside>
        <h4>Files</h4>
        <ul>{files}</ul>
      </aside>
    </section>
  );
}

async function myCustomFileGetter(event) {
  const files = [];
  const fileList = event.dataTransfer ? event.dataTransfer.files : event.target.files;

  for (var i = 0; i < fileList.length; i++) {
    const file = fileList.item(i);
    
    Object.defineProperty(file, 'myProp', {
      value: true
    });

    files.push(file);
  }

  return files;
}

<Plugin />