export declare class PromiseCancelledSignal {
}
export declare function findIndex<T>(array: ReadonlyArray<T>, condition: (t: T) => unknown): number;
export declare function makeCancellable<T>(promise: Promise<T>): {
    promise: Promise<T>;
    cancel: () => void;
    isCancelled: () => boolean;
};
export declare function useMemoizedArray<T>(array: ReadonlyArray<T>, isEqual: (prev: T, next: T) => boolean): ReadonlyArray<T>;