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Server-time-based expiry/reward logic

getServerTime() returns the server-side Unix timestamp in milliseconds asynchronously. Because the client device clock can be changed by the user, any time comparison that needs to be trustworthy — expiry checks, reward eligibility — should use getServerTime() instead of Date.now().

Check whether an event is still active​

import { getServerTime } from '@apps-in-toss/web-framework';
import { useState, useEffect } from 'react';

const EVENT_END_MS = 1_720_000_000_000; // event end timestamp (Unix ms)

type Status = 'loading' | 'active' | 'expired' | 'unsupported';

function EventPage() {
  const [status, setStatus] = useState<Status>('loading');

  useEffect(() => {
    async function check() {
      if (!getServerTime.isSupported()) {
        setStatus('unsupported');
        return;
      }

      const serverTime = await getServerTime();
      if (serverTime === undefined) {
        setStatus('unsupported');
        return;
      }

      setStatus(serverTime <= EVENT_END_MS ? 'active' : 'expired');
    }

    check();
  }, []);

  const label: Record<Status, string> = {
    loading: 'Checking…',
    active: 'You can participate in this event.',
    expired: 'This event has ended.',
    unsupported: 'This feature is not available in your current app version.',
  };

  return <p>{label[status]}</p>;
}

Always call getServerTime.isSupported() first, then handle the undefined return case before using the timestamp.

Reward cooldown check​

import { getServerTime } from '@apps-in-toss/web-framework';

const COOLDOWN_MS = 24 * 60 * 60 * 1000; // 24 hours

async function canClaimReward(lastClaimedAt: number): Promise<boolean> {
  if (!getServerTime.isSupported()) {
    // Conservative fallback: deny if we can't verify
    return false;
  }

  const serverTime = await getServerTime();
  if (serverTime === undefined) return false;

  return serverTime - lastClaimedAt >= COOLDOWN_MS;
}

lastClaimedAt should come from the server, not from localStorage. Comparing two server-derived timestamps keeps the check tamper-proof.