A filterable list shows a notification whenever the filter input changes.
The "Filter applied" notification appears immediately on page load before the user has typed anything in the filter box.
The effect fires on mount - is that always the right time to show the toast?
The effect fires on mount - is that always the right time to show the toast?
Why this fixes it
The broken code called `setToast("Filter applied")` unconditionally, so the effect fired on mount when `filter` was still an empty string and the toast appeared before the user had typed anything. Replacing the body with `setToast(filter ? "Filter applied" : "")` makes the toast directly reactive to the filter value - when `filter` is empty the toast is cleared, and when it is non-empty the toast is shown. This also correctly resets the toast when the user clears the input after typing, which the previous guard-based approach failed to handle.