on web you can use LocalStorage as asyncstorage on React Native, you can visit this link for more information about local-storage developer.mozilla.org/en-US/docs/Web/API/Window/l…
but this solution can be for simple data only, if you have many data like users, posts ... etc, then you need to use different tool to store your data like Firebase, or create your custom API. watch this video for more details about using Firebase with React youtube.com/watch