По теме "ончейн это", есть отличная статья. Смотрите сами: <a href=https://reactive.su/%D0%BE%D0%BD%D1%87%D0%B5%D0%B9%D0%BD-%D0%B0%D0%BD%D0%B0%D0%BB%D0%B8%D0%B7-%D1%87%D1%82%D0%BE-%D1%8D%D1%82%D0%BE-%D0%B8-%D0%BA%D0%B0%D0%BA-%D0%B8%D1%81%D0%BF%D0%BE%D0%BB%D1%8C%D0%B7%D0%BE%D0%B2%D0%B0/>https://reactive.su/%D0%BE%D0%BD%D1%87%D0%B5%D0%B9%D0%BD-%D0%B0%D0%BD%D0%B0%D0%BB%D0%B8%D0%B7-%D1%87%D1%82%D0%BE-%D1%8D%D1%82%D0%BE-%D0%B8-%D0%BA%D0%B0%D0%BA-%D0%B8%D1%81%D0%BF%D0%BE%D0%BB%D1%8C%D0%B7%D0%BE%D0%B2%D0%B0/</a>