Toast serves as a feedback & confirmation mechanism after the user takes an action.
Notifications should contain
role="status" on the container to signal to
assistive technology that they require the user’s attention. Historically the role of
alert would be used,
but because you can invoke multiple toasts, assertive alerts would override previous toasts in the screen
reader's speech queue. Role of
status is a polite live region, which does not clear the queue, reducing the risk
of a toast message being missed.
Use a span with
slds-assistive-text to let the user know what type of notification it is.