Initial commit with 🏗️ Scaffold-ETH 2 @ 1.0.5

packages/nextjs/utils/scaffold-eth/fetchPriceFromUniswap.ts

@@ -0,0 +1,72 @@
+import { ChainWithAttributes, getAlchemyHttpUrl } from "./networks";
+import { CurrencyAmount, Token } from "@uniswap/sdk-core";
+import { Pair, Route } from "@uniswap/v2-sdk";
+import { Address, createPublicClient, fallback, http, parseAbi } from "viem";
+import { mainnet } from "viem/chains";
+
+const alchemyHttpUrl = getAlchemyHttpUrl(mainnet.id);
+const rpcFallbacks = alchemyHttpUrl ? [http(alchemyHttpUrl), http()] : [http()];
+const publicClient = createPublicClient({
+  chain: mainnet,
+  transport: fallback(rpcFallbacks),
+});
+
+const ABI = parseAbi([
+  "function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast)",
+  "function token0() external view returns (address)",
+  "function token1() external view returns (address)",
+]);
+
+export const fetchPriceFromUniswap = async (targetNetwork: ChainWithAttributes): Promise<number> => {
+  if (
+    targetNetwork.nativeCurrency.symbol !== "ETH" &&
+    targetNetwork.nativeCurrency.symbol !== "SEP" &&
+    !targetNetwork.nativeCurrencyTokenAddress
+  ) {
+    return 0;
+  }
+  try {
+    const DAI = new Token(1, "0x6B175474E89094C44Da98b954EedeAC495271d0F", 18);
+    const TOKEN = new Token(
+      1,
+      targetNetwork.nativeCurrencyTokenAddress || "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
+      18,
+    );
+    const pairAddress = Pair.getAddress(TOKEN, DAI) as Address;
+
+    const wagmiConfig = {
+      address: pairAddress,
+      abi: ABI,
+    };
+
+    const reserves = await publicClient.readContract({
+      ...wagmiConfig,
+      functionName: "getReserves",
+    });
+
+    const token0Address = await publicClient.readContract({
+      ...wagmiConfig,
+      functionName: "token0",
+    });
+
+    const token1Address = await publicClient.readContract({
+      ...wagmiConfig,
+      functionName: "token1",
+    });
+    const token0 = [TOKEN, DAI].find(token => token.address === token0Address) as Token;
+    const token1 = [TOKEN, DAI].find(token => token.address === token1Address) as Token;
+    const pair = new Pair(
+      CurrencyAmount.fromRawAmount(token0, reserves[0].toString()),
+      CurrencyAmount.fromRawAmount(token1, reserves[1].toString()),
+    );
+    const route = new Route([pair], TOKEN, DAI);
+    const price = parseFloat(route.midPrice.toSignificant(6));
+    return price;
+  } catch (error) {
+    console.error(
+      `useNativeCurrencyPrice - Error fetching ${targetNetwork.nativeCurrency.symbol} price from Uniswap: `,
+      error,
+    );
+    return 0;
+  }
+};