update.rs

Finally we have the update.rs file. Here, the update() function takes in two arguments:

• key_event: This is an event provided by the crossterm crate, representing a key press from the user.
• app: A mutable reference to our application's state, represented by the App struct.

{{#include @code/tutorials/ratatui-counter-app/src/update.rs}}

Note that here we don't have to check that key_event.kind is KeyEventKind::Press because we already do that check in event.rs and only send KeyEventKind::Press events on the channel.

:::note[Homework]

As an exercise, can you refactor this app to use "The Elm Architecture" principles?

Check out the concepts page on The Elm Architecture for reference.

:::