import { useEffect, useMemo, useState } from "react"; import { JsonRpcProvider, BlockTag } from "@ethersproject/providers"; import { Contract } from "@ethersproject/contracts"; import { BigNumber } from "@ethersproject/bignumber"; import AggregatorV3Interface from "@chainlink/contracts/abi/v0.8/AggregatorV3Interface.json"; export const useETHUSDOracle = ( provider: JsonRpcProvider | undefined, blockTag: BlockTag | undefined ) => { const priceMap = useMultipleETHUSDOracle(provider, [blockTag]); if (blockTag === undefined) { return undefined; } return priceMap[blockTag]; }; export const useMultipleETHUSDOracle = ( provider: JsonRpcProvider | undefined, blockTags: (BlockTag | undefined)[] ) => { const ethFeed = useMemo(() => { if (!provider || provider.network.chainId !== 1) { return undefined; } try { return new Contract("eth-usd.data.eth", AggregatorV3Interface, provider); } catch (err) { console.error(err); return undefined; } }, [provider]); const [latestPriceData, setLatestPriceData] = useState< Record >({}); useEffect(() => { if (!ethFeed) { return; } const priceReaders: Promise[] = []; for (const blockTag of blockTags) { priceReaders.push( (async () => { try { const priceData = await ethFeed.latestRoundData({ blockTag }); return BigNumber.from(priceData.answer); } catch (err) { console.error(err); return undefined; } })() ); } const readData = async () => { const results = await Promise.all(priceReaders); const priceMap: Record = {}; for (let i = 0; i < blockTags.length; i++) { const blockTag = blockTags[i]; const result = results[i]; if (blockTag === undefined || result === undefined) { continue; } priceMap[blockTag] = result; } setLatestPriceData(priceMap); }; readData(); }, [ethFeed, blockTags]); return latestPriceData; };