Interface ScreenItemFieldShape<Items, Form, Failure>

The brand of a handle field over the screen's own items — Items is the item list they come from ({ at, key, item } or { at, key, by, variants }), so each item shows its list's identity key — typed by the handle itself so an edge taken from one of its items backs to that handle: maybe — one item, or undefined (a swipeable feed's current, the item in front); stream — a lazy stream of them that may fail with Failure (a feed's stream, walked by pages or, on a swipeable feed, by swipes).