@hypotenuselabs/ts-chainlink-datafeed NPM

⭐️ ts-chainlink-datafeed ⭐️

This TypeScript project provides a ChainLink datafeed library that can be used to retrieve data from any EVM chain on http://data.chain.link.

🚀 Use cases

You want to read a single data feed like ETH/USD on Ethereum/Polygon/Arbitrum etc?

import { polygonDataFeeds } from "@hypotenuselabs/ts-chainlink-datafeed";
import { createPublicClient, http } from "viem";
import { polygon } from "viem/chains";

const RPCUrl = "https://your-rpc-url.com"; // https://chainlist.org for a list of public RPCs

const callClient = createPublicClient({
  transport: http(RPCUrl), // can also use websocket(RPCUrl) for websocket RPCs
  chain: polygon,
  batch: {
    multicall: true,
  },
});

// All possible data feeds for Polygon
const EthUSD = polygonDataFeeds["ETH / USD"];

const ethUsdDataFeed = new ChainLinkDataFeed({
  chain: polygon,
  contractAddress: EthUSD,
  viemClient: publicClient,
});


setInterval(() => {
  console.log(
    await ethUsdDataFeed.getLatestRoundData(true)
  );
}, 5000) // You can use this to update the price every 5 seconds
/**
* {
*  roundId: 36893488147426144869n,
*  answer: '2379.44', // $2379.44
*  time: 2024-01-10T13:08:43.000Z,
*  description: 'ETH / USD'
* }  
*/

You want to subscribe to a single data feed for ETH/USD on Ethereum/Polygon/Arbitrum etc?

// You can use the same RPC public client setup as above.
const ethUsdFeed = polygonDataFeeds["ETH / USD"];

subscribeToChainLinkPriceUpdates({
  feedAddresses: [...ethUsdFeed],
  publicClient: callClient,
  onLogsFunction: (arrayOfLogs) => 
    arrayOfLogs.forEach((log) => {
      // every time there is an update on chain, this function will be called
      console.log(`Asset: ${log.description}`); // ETH / USD - The description of the data feed
      console.log(`Decimals: ${log.decimals}`); // The number of decimals the answer uses
      console.log(`🔘 Round ID: ${log.roundId}`); // The roundId of the answer
      console.log(`📈 Answer: ${log.current}`); // The price of the asset without decimals
      console.log(`⏰ Time: ${log.updatedAt}`); // The time the answer was last updated
    }),
});

More detailed examples can be found in the example folder.

You want to subscribe to multiple data feeds on a single chain?

const feeds = [
  polygonDataFeeds["ETH / USD"],
  polygonDataFeeds["BTC / USD"],
  polygonDataFeeds["LINK / USD"],
  polygonDataFeeds["UNI / USD"],
  polygonDataFeeds["USDC / USD"],
  polygonDataFeeds["USDT / USD"],
  polygonDataFeeds["WBTC / USD"],
  polygonDataFeeds["wstETH-stETH Exchange Rate"],
]

subscribeToChainLinkPriceUpdates({
  feedAddresses: feeds,
  publicClient: callClient,
  onLogsFunction: (arrayOfLogs) => 
    arrayOfLogs.forEach((log) => {
      // every time there is an update on chain, this function will be called
      console.log(`Asset: ${log.description}`); // ETH / USD - The description of the data feed
      console.log(`Decimals: ${log.decimals}`); // The number of decimals the answer uses
      console.log(`🔘 Round ID: ${log.roundId}`); // The roundId of the answer
      console.log(`📈 Answer: ${log.current}`); // The price of the asset without decimals
      console.log(`⏰ Time: ${log.updatedAt}`); // The time the answer was last updated
    }),
});

More detailed examples can be found in the example folder.

You want to subscribe to multiple data feeds on multiple chains?

import { polygon, ethereum } from "viem/chains";

const ethereumClient = createPublicClient({
  transport: http(ethereumRpcUrl), // can also use websocket(RPCUrl) for websocket RPCs
  chain: ethereum,
  batch: {
    multicall: true,
  },
});

const ethereumFeeds = [
  ethereumDataFeeds["ETH / USD"],
  ethereumDataFeeds["BTC / USD"],
]

subscribeToChainLinkPriceUpdates({
  feedAddresses: feeds,
  publicClient: polygonClient,
  onLogsFunction: (arrayOfLogs) => 
    arrayOfLogs.forEach((log) => {
      // every time there is an update on chain, this function will be called
      console.log(`Asset: ${log.description}`); // ETH / USD - The description of the data feed
      console.log(`Decimals: ${log.decimals}`); // The number of decimals the answer uses
      console.log(`🔘 Round ID: ${log.roundId}`); // The roundId of the answer
      console.log(`📈 Answer: ${log.current}`); // The price of the asset without decimals
      console.log(`⏰ Time: ${log.updatedAt}`); // The time the answer was last updated
    }),
});

const polygonClient = createPublicClient({
  transport: http(polygonRpcUrl), // can also use websocket(RPCUrl) for websocket RPCs
  chain: polygon,
  batch: {
    multicall: true,
  },
});

const polygonFeeds = [
  polygonDataFeeds["ETH / USD"],
  polygonDataFeeds["BTC / USD"],
]

subscribeToChainLinkPriceUpdates({
  feedAddresses: feeds,
  publicClient: polygonClient,
  onLogsFunction: (arrayOfLogs) => 
    arrayOfLogs.forEach((log) => {
      // every time there is an update on chain, this function will be called
      console.log(`Asset: ${log.description}`); // ETH / USD - The description of the data feed
      console.log(`Decimals: ${log.decimals}`); // The number of decimals the answer uses
      console.log(`🔘 Round ID: ${log.roundId}`); // The roundId of the answer
      console.log(`📈 Answer: ${log.current}`); // The price of the asset without decimals
      console.log(`⏰ Time: ${log.updatedAt}`); // The time the answer was last updated
    }),
});

More detailed examples can be found in the example folder.

You want to subscribe to data feeds in a React application?

import { createPublicClient, fallback, http } from "viem";
import { Row } from "./@/components/Row";
import { polygon } from "viem/chains";
import {
  polygonDataFeeds,
  useDataFeed,
} from "@hypotenuselabs/ts-chainlink-datafeed";

const PolygonRPCList = [
  "https://1rpc.io/matic",
]

const transports = fallback(PolygonRPCList.map((rpc) => http(rpc)));

const polygonClient = createPublicClient({
  transport: transports,
  chain: polygon,
  batch: {
    multicall: true,
  },
});

export default function App() {
  const polygon = useDataFeed({
    viemClient: polygonClient,
    chainDataFeeds: polygonDataFeeds,
    feedsToSubscribeTo: Object.keys(polygonDataFeeds),
  });

  const feed = Object.values(polygon);
  const length = Object.keys(polygonDataFeeds).length;

  return (
    <main className="max-w-[1080px] m-auto my-10">
      <Row
        chainName={`Polygon - As prices update onchain, they will be displayed below. Total feeds: ${length}`}
        feeds={feed}
      />
    </main>
  );
}

See datafeeds-example-site repo and a live running example at https://chainlink-datafeeds-example-taupe.vercel.app/

📋 Features

Get the latest price of any asset featured on Chainlink.
Redundant RPC support so that you never miss a price update.
No reliance on 3rd party APIs like CoinGecko or CoinMarketCap.
Supports Ethereum, Polygon, Arbitrum, Xdai, Harmony, Moonriver, Celo, Bsc, Optimism, Avalanche, Fantom, Base, Moonbeam, Metis, Scroll and more.

🛠️ Setup

# Yarn
yarn add @hypotenuselabs/ts-chainlink-datafeed
# NPM
npm install @hypotenuselabs/ts-chainlink-datafeed

🛜 RPCs

You can get multiple RPCs for each chain from Chainlist. If you create a fallback provider, you can have a redundant list of RPCs incase one fails or is slow to respond. The example has some code to help with this. You can use both http and websocket RPCs.

You can distribute requests round robin by installing @ponder/utils.

import { loadBalance } from "@ponder/utils";
const polygonRpcList = [
  "https://public.stackup.sh/api/v1/node/polygon-mainnet",
  "https://polygon.gateway.tenderly.co",
];

const transports = loadBalance(
  polygonRpcList.map((rpc) => useWebsocketOrHttpTransport(rpc))
);

const polyCallClient = createPublicClient({
  name: "PolyCall",
  transport: transports,
  chain: polygon,
});

📦 Supported Chains - Extracting a feed

You can get a single feed by importing the chain feed constant that you need and selecting the feed you want. For example, if you want the ETH / USD feed on Polygon, you would do the following:

import { polygonDataFeeds } from "@hypotenuselabs/ts-chainlink-datafeed";

const EthUSD = polygonDataFeeds["ETH / USD"];
// 0xF9680D99D6C9589e2a93a78A04A279e509205945

🧵 Custom Chains

If you are using a chain that does not have a chain configuration in Viem, you can easily create your own. See this example for Scroll.

🤖 Chainlink Contract Address Scaper

By running the updateAllFeeds command in the package.json, you can update all of the datafeed helper constants automatically. This function will load up a Chrome browser in headless mode and scrape all of the contract addresses for every single listed feed on the official Chainlink website.