function performScheduledUpdateOfDataInRedis(index, url, fn = null) {
    //updateDataInRedis(index, url, fn);
    console.info(getTimeLeftBeforeUpdate());
    setTimeout(function () {
        return performScheduledUpdateOfDataInRedis(index, url, fn);
    }, getTimeLeftBeforeUpdate());
}

module.exports = {
    scheduleUpdatesInRedis :  (index, url, fn = null) => {
        console.info(`Updates of ${index} [${url}] in redis have been scheduled`);
        setTimeout(() => {
            console.info('performScheduledUpdateOfDataInRedis(index, url, fn);');
            return performScheduledUpdateOfDataInRedis(index, url, fn); // It will be called infinitely unless interrupted
        }, getTimeLeftBeforeUpdate());
    },

    scheduleRanksUpdates : () => {
        console.info(`Updates of ranks in redis have been scheduled`);
        setTimeout(() => {
            return performScheduledRanksUpdatesInRedis(); // It will be called infinitely unless interrupted
        }, getTimeLeftBeforeUpdate());
    }
}

OUTPUT:
"performScheduledUpdateOfDataInRedis(index, url, fn);
31518656000
31518656000
31518656000
31518656000
31518656000
31518656000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000
31518655000"