Интерфейс ReactChildren

interface ReactChildren {
    count(children: any): number;
    forEach<C>(children: C | C[], fn: (child: C, index: number) => void): void;
    map<T, C>(
        children: C | C[],
        fn: (child: C, index: number) => T,
    ): C extends null
    | undefined
        ? C<C>
        : Exclude<T, boolean | null | undefined>[];
    only<C>(children: C): C extends any[] ? never : C;
    toArray(
        children: ReactNode | ReactNode[],
    ): (ReactChild | ReactFragment | ReactPortal)[];
}