Chainlink price feeds for wARS and wBRL

import { createPublicClient, http, parseAbi } from 'viem';
import { base } from 'viem/chains';

const ARS_USD = '0xaf992a6ad37b4878cF9c31f082B178860e268cE3'; // Base
const FEED_ABI = parseAbi([
  'function decimals() view returns (uint8)',
  'function latestRoundData() view returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound)',
]);

const client = createPublicClient({ chain: base, transport: http(process.env.BASE_RPC_URL) });

const [decimals, [, answer, , updatedAt]] = await Promise.all([
  client.readContract({ address: ARS_USD, abi: FEED_ABI, functionName: 'decimals' }),
  client.readContract({ address: ARS_USD, abi: FEED_ABI, functionName: 'latestRoundData' }),
]);

// Set the limit per feed: its heartbeat plus a margin. This feed has a 24-hour heartbeat
const MAX_AGE_SECONDS = 26n * 60n * 60n;
if (answer <= 0n) throw new Error('Invalid ARS/USD answer');
if (BigInt(Math.floor(Date.now() / 1000)) - updatedAt > MAX_AGE_SECONDS) throw new Error('Stale ARS/USD answer');

const usdPerArs = Number(answer) / 10 ** decimals; // illustrative: about 0.0006 USD per ARS
const arsPerUsd = 1 / usdPerArs;