Create index.ts

index.ts

@@ -0,0 +1,160 @@
+import { config as dotenv } from "dotenv";
+import {
+  createWalletClient,
+  http,
+  getContract,
+  erc20Abi,
+  parseUnits,
+  maxUint256,
+  publicActions,
+  concat,
+  numberToHex,
+  size,
+} from "viem";
+import type { Hex } from "viem";
+import { privateKeyToAccount } from "viem/accounts";
+import { scroll } from "viem/chains";
+import { wethAbi } from "./abi/weth-abi";
+
+// For the 0x Challenge on Scroll, implement the following:
+// 1. Display the percentage breakdown of liquidity sources
+// 2. Monetize your app with affiliate fees and surplus collection
+// 3. Display buy/sell tax for tokens with tax
+// 4. Display all sources of liquidity on Scroll
+
+const qs = require("qs");
+
+// Load environment variables
+dotenv();
+const { PRIVATE_KEY, ZERO_EX_API_KEY, ALCHEMY_HTTP_TRANSPORT_URL } = process.env;
+
+// Validate environment variables
+if (!PRIVATE_KEY) throw new Error("Missing PRIVATE_KEY.");
+if (!ZERO_EX_API_KEY) throw new Error("Missing ZERO_EX_API_KEY.");
+if (!ALCHEMY_HTTP_TRANSPORT_URL) throw new Error("Missing ALCHEMY_HTTP_TRANSPORT_URL.");
+
+// Set request headers
+const headers = new Headers({
+  "Content-Type": "application/json",
+  "0x-api-key": ZERO_EX_API_KEY,
+  "0x-version": "v2",
+});
+
+// Initialize wallet client
+const client = createWalletClient({
+  account: privateKeyToAccount(`0x${PRIVATE_KEY}` as `0x${string}`),
+  chain: scroll,
+  transport: http(ALCHEMY_HTTP_TRANSPORT_URL),
+}).extend(publicActions); // Extend wallet client with public actions
+
+const [address] = await client.getAddresses();
+
+// Set up contracts
+const weth = getContract({
+  address: "0x5300000000000000000000000000000000000004",
+  abi: wethAbi,
+  client,
+});
+
+const wsteth = getContract({
+  address: "0xf610A9dfB7C89644979b4A0f27063E9e7d7Cda32",
+  abi: erc20Abi,
+  client,
+});
+
+const main = async () => {
+  // Specify sell amount
+  const decimals = await weth.read.decimals() as number;
+  const sellAmount = parseUnits("0.1", decimals);
+
+  // Fetch price
+  const priceParams = new URLSearchParams({
+    chainId: client.chain.id.toString(),
+    sellToken: weth.address,
+    buyToken: wsteth.address,
+    sellAmount: sellAmount.toString(),
+    taker: client.account.address,
+  });
+
+  const priceResponse = await fetch(
+    `https://api.0x.org/swap/permit2/price?${priceParams.toString()}`,
+    { headers }
+  );
+  const price = await priceResponse.json();
+  console.log("Fetching price to swap 0.1 WETH for wstETH", price);
+
+  // Check if allowance needs to be set for Permit2
+  if (price.issues?.allowance !== null) {
+    try {
+      const { request } = await weth.simulate.approve([
+        price.issues.allowance.spender,
+        maxUint256,
+      ]);
+      console.log("Approving Permit2 to spend WETH...", request);
+
+      // Set approval
+      const hash = await weth.write.approve(request.args);
+      console.log(
+        "Approved Permit2 to spend WETH.",
+        await client.waitForTransactionReceipt({ hash })
+      );
+    } catch (error) {
+      console.error("Error approving Permit2:", error);
+    }
+  } else {
+    console.log("WETH already approved for Permit2");
+  }
+
+  // Fetch quote
+  const quoteParams = new URLSearchParams(priceParams);
+  const quoteResponse = await fetch(
+    `https://api.0x.org/swap/permit2/quote?${quoteParams.toString()}`,
+    { headers }
+  );
+  const quote = await quoteResponse.json();
+  console.log("Fetching quote to swap 0.1 WETH for wstETH", quote);
+
+  // Sign permit2.eip712 returned from quote
+  let signature: Hex | undefined;
+  if (quote.permit2?.eip712) {
+    try {
+      signature = await client.signTypedData(quote.permit2.eip712);
+      console.log("Signed permit2 message from quote response");
+    } catch (error) {
+      console.error("Error signing permit2 coupon:", error);
+    }
+
+    // Append signature to transaction data
+    if (signature && quote?.transaction?.data) {
+      const sigLengthHex = numberToHex(size(signature), { signed: false, size: 32 }) as Hex;
+      const sig = signature as Hex;
+      quote.transaction.data = concat([quote.transaction.data as Hex, sigLengthHex, sig]);
+    } else {
+      throw new Error("Failed to obtain signature or transaction data");
+    }
+  }
+
+  // Submit transaction with permit2 signature
+  if (signature && quote.transaction.data) {
+    const nonce = await client.getTransactionCount({ address: client.account.address });
+
+    const signedTransaction = await client.signTransaction({
+      account: client.account,
+      chain: client.chain,
+      gas: quote?.transaction.gas ? BigInt(quote.transaction.gas) : undefined,
+      to: quote?.transaction.to,
+      data: quote.transaction.data,
+      value: quote?.transaction.value ? BigInt(quote.transaction.value) : undefined,
+      gasPrice: quote?.transaction.gasPrice ? BigInt(quote.transaction.gasPrice) : undefined,
+      nonce,
+    });
+    const hash = await client.sendRawTransaction({ serializedTransaction: signedTransaction });
+
+    console.log("Transaction hash:", hash);
+    console.log(`See transaction details at https://scrollscan.com/tx/${hash}`);
+  } else {
+    console.error("Failed to obtain a signature, transaction not sent.");
+  }
+};
+
+main();