How to use the react-native-video.TextTrackType.VTT function in react-native-video

Object.keys(foundSubtitles).forEach((langCode) => {
      const sub = foundSubtitles[langCode]

      subs.push({
        title   : sub.lang,
        language: sub.langcode,
        type    : TextTrackType.VTT, // "text/vtt"
        uri     : sub.vtt,
      })
    })

it("must has values", () => {
    (TextTrackType.SRT: "application/x-subrip");
    (TextTrackType.TTML: "application/ttml+xml");
    (TextTrackType.VTT: "text/vtt");
  });
});

it('should has values', () => {
    (TextTrackType.SRT: 'application/x-subrip');
    (TextTrackType.TTML: 'application/ttml+xml');
    (TextTrackType.VTT: 'text/vtt');
  });