/**
 * Which ids are new, given what was on screen before — the rule, without React.
 *
 * `before` is `null` when nothing has been seen yet, and that case is the whole
 * reason this is a named function: **a first render is never an arrival.** A
 * register opening on two hundred rows has two hundred ids it has not seen, and
 * the naive diff flashes all of them — both wrong (nothing arrived, the page
 * loaded) and the moment a highlight is least wanted.
 *
 * A removal reports nothing. A row leaving is not a row arriving, and the two
 * share a diff only if you write it carelessly.
 */
export declare function arrivalsSince(before: ReadonlySet<string> | null, ids: readonly string[]): string[];
/**
 * Which of these ids are NEW since the last render — the set a register passes
 * to `TableRow`'s `justArrived`.
 *
 * A row landing while someone is looking at the screen is the case the realtime
 * push exists for, and until something marks it the push is invisible: the list
 * is one row longer and nothing says which one. Every register wants the same
 * diff, so it lives here rather than in each app.
 *
 * **`scope` is what the ids are a list OF** — the filter, the search, the page.
 * Without it a register cannot tell twelve rows ARRIVING from a filter change
 * that replaced the list, because both are a large diff, and it would flash the
 * whole page every time someone picked a status. Change the scope and the
 * baseline reseeds silently: nothing arrived, the reader asked a different
 * question. Pass a string that changes exactly when the QUESTION does.
 *
 * An EMPTY render never seeds the baseline either: a list rendering `[]` while
 * its query is in flight would otherwise make its real first page look like an
 * arrival.
 *
 * Ids leave the set on the next render that carries them, so the highlight is a
 * one-shot — re-rendering never restarts an animation that already played.
 */
export declare function useJustArrived(ids: readonly string[], scope?: string): ReadonlySet<string>;