When should a toast arise in web app (need psychological suggestion)?
Add to favorite action has no toast, while
Delete actions have ones?
Toasts or snackbars are used for low-priority notifications, like pictured.
User Experience Stack Exchange is a question and answer site for user experience researchers and experts. It only takes a minute to sign up.Sign up to join this community
Answering your first question:
When should a toast arise in web app?
A toast should arise directly after:
The reason for a toast arising directly after actions or system changes is to provide immediate system feedback, which aims to reassure the user that their action is completed or not or if any state changes have occurred, and therefore it must be done in a timely manner.
In regards to your second question:
Why Add to favorite action has no toast, while Archive or Delete actions have ones?
You'll have to ask the designers of the app in question. It's up to them so we cannot help you here other than a guess. My guess is that Archive and Delete removes the item from the list which is a "risky" action, if the user mistakenly taps this button at least they'll know what has happened to that list item. Whereas, Add to favourites, I guess, just add it to another list whilst not moving it from the current one.
From my UX viewpoint, notifications as toasts are good once I'm as a end-user is informed with something that is not so important or I'm surely aware of it as I triggered it explicitly, AND there is no damage if the toast is missed by me at all (let say, I'm eventually turned to my coffee machine for the next drink, or massaging my closed eyes etc.)
In case you need to be sure the notification is read, you could show closable banner (so it stays visible until X-clicked, however it's not covering valuable information on the page (so end-user can keep his working with or without X-clicking the banner)
In case you have to stop any further end-user action before reacting on the notification, use local popups.