To me a reactive data source would be something like Asana, Trello, Teamwork or on an ecommerce site it could be the cart widget. Basically any type of data tha

To me a reactive data source would be something like Asana, Trello, Teamwork or on an ecommerce site it could be the cart widget. Basically any type of data that needs to react without requiring a page reload or any data source that needs to sync with another users inputs in real time.