export interface UpdatedOptions { key?: (thing: T, index?: number) => string; equals?: (thingA: T, thingB: T) => boolean; onEnter?: (newThing: T) => void; onUpdate?: (newThing: T, oldThing: T) => void; onExit?: (oldThing: T) => void; } export declare function updater(oldThings: T[], newThings: T[], updatedOptions: UpdatedOptions): void;