const containsPromises: unique symbol = Symbol();

type DeepPromised<T> =
    { [containsPromises]?: true } &
    {
        [TKey in keyof T]: T[TKey] | DeepPromised<T[TKey]> | Promise<DeepPromised<T[TKey]>>
    };

async function fun<T>(deepPromised: DeepPromised<T>) {

    const deepPromisedWithIndexer:
        DeepPromised<{ [name: string]: {} | null | undefined }> = deepPromised;

    for (const value of Object.values(deepPromisedWithIndexer)) {

        const awaitedValue = await value;

        if (awaitedValue)
            await fun(awaitedValue);
    }
}