display-price.js

{
    displayPrice: (function() {
        const PRICE_CACHE = [];
        
        return function _displayPrice(eventIndex) {
            if (!PRICE_CACHE[eventIndex]) {
                const tickets = this.ticketsByEvent[eventIndex];

                if (tickets && tickets.length > 0) {
                    tickets.sort((a, b) => a.price - b.price);

                    const min = tickets[0].price;
                    const max = tickets.slice(-1)[0].price;
                    
                    PRICE_CACHE[eventIndex] = `N${min}${min === max ? "" : ` - N${max}`}`;
                } else return "";
            }
            
            return PRICE_CACHE[eventIndex];
        };
    })()
}

events-tickets.js

{
    async asyncData({ error }) {
        try {
            const events = await EventService.getEvents();

            (function _fetchEventTickets() {
                const REFETCH_DELAY_DURATION = 10 * 1000; // 10s
                const FAILED_ATTEMPTS = new Map();

                function _fetchEventTicket(id, index) {
                    return EventService.getEventTicketTypes(id)
                        .then(tickets => { events[index].tickets = tickets })
                        .catch(() => { FAILED_ATTEMPTS.set(id, index) });
                }

                function _refetchEventTickets() {
                    _fetchEventTicketsPromises(
                        [...FAILED_ATTEMPTS.entries()].map(([id, index]) => {
                            FAILED_ATTEMPTS.delete(id);
                            return _fetchEventTicket(id, index);
                        })
                    );
                }
                
                function _scheduleRefetchEventTickets() {
                    if (FAILED_ATTEMPTS.size > 0) {
                        setTimeout(_refetchEventTickets, REFETCH_DELAY_DURATION);
                    }
                }
                
                function _fetchEventTicketsPromises(promises) {
                    Promise.all(promises).then(
                        _scheduleRefetchEventTickets,
                        _scheduleRefetchEventTickets
                    );
                }

                _fetchEventTicketsPromises(
                    events.map(({ id }, index) => _fetchEventTicket(id, index))
                );
            })();

            return { events }
        } catch (err) {
            error(err);
        }
    }
}