React hook for turning a string into a downloadable txt-file

useTxtBlobifier.tsx

/**
 * This hook returns an URL you can use in the href-attribute of an anchor element,
 * so the provided string will be downloaded as a txt-file.
 */
function useTxtBlobifier(document: string) {
  const [loading, setLoading] = useState(true);
  const [url, setUrl] = useState('');

  // Remove the unused url instance if/when the document
  // changes, or when component unmounts.
  useEffect(() => {
    return () => {
      if (url) {
        URL.revokeObjectURL(url);
      }
    };
  }, [url]);

  const instance = { loading, url };

  useEffect(
    function () {
      if (document && typeof document === 'string') {
        // Fix typesetting issues if document is opened in the browser
        // (typically new tab, instead of downloading)
        const BOM = new Uint8Array([0xef, 0xbb, 0xbf]);

        const blob = new Blob([BOM, document], {
          type: 'text/plain',
        });

        setUrl(URL.createObjectURL(blob));
        setLoading(false);
      } else {
        setLoading(true);
      }
    },
    [document]
  );

  return { url, loading };
}


// TODO: I could release a component into npm that resembles react-pdf, only for txt-files instead.