From 329a1fdf9654527cd5f10634bffc50c9e9f0b0c4 Mon Sep 17 00:00:00 2001
From: hzhu <hz@henryzhu.me>
Date: Wed, 10 Jul 2024 10:28:50 -0700
Subject: [PATCH] fix: erc-20 transfers for SettlerMetaTxn

---
 src/parseSwapV2.ts            | 14 +++++++++-----
 src/tests/parseSwapV2.test.ts | 31 +++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/src/parseSwapV2.ts b/src/parseSwapV2.ts
index 84180d6..84d9b09 100644
--- a/src/parseSwapV2.ts
+++ b/src/parseSwapV2.ts
@@ -303,11 +303,15 @@ export async function parseSwapV2({
 
     const nativeTransferAmount = extractNativeTransfer(trace, taker);
 
-    output = {
-      symbol: NATIVE_SYMBOL_BY_CHAIN_ID[chainId],
-      amount: nativeTransferAmount,
-      address: NATIVE_TOKEN_ADDRESS,
-    };
+    if (nativeTransferAmount === "0") {
+      output = logs[logs.length - 1];
+    } else {
+      output = {
+        symbol: NATIVE_SYMBOL_BY_CHAIN_ID[chainId],
+        amount: nativeTransferAmount,
+        address: NATIVE_TOKEN_ADDRESS,
+      };
+    }
   }
 
   if (isNativeSell) {
diff --git a/src/tests/parseSwapV2.test.ts b/src/tests/parseSwapV2.test.ts
index 9736d9d..4ff6130 100644
--- a/src/tests/parseSwapV2.test.ts
+++ b/src/tests/parseSwapV2.test.ts
@@ -445,6 +445,37 @@ test("parse a gasless swap on Base (USDC for ETH) for SettlerMetaTxn", async ()
   });
 });
 
+// https://basescan.org/tx/0xe595dec22a7e2c2c5bdb0c1a7e59b2302ede72e5d2210c6cd7071222ea6dc2b2
+test("parse a gasless swap on Base (DEGEN for USDC) for SettlerMetaTxn", async () => {
+  const publicClient = createPublicClient({
+    chain: base,
+    transport: http(
+      `https://base-mainnet.g.alchemy.com/v2/${process.env.ALCHEMY_API_KEY}`
+    ),
+  }) as PublicClient<Transport, Chain>;
+
+  const transactionHash =
+    "0xe595dec22a7e2c2c5bdb0c1a7e59b2302ede72e5d2210c6cd7071222ea6dc2b2";
+
+  const result = await parseSwapV2({
+    publicClient,
+    transactionHash,
+  });
+
+  expect(result).toEqual({
+    tokenIn: {
+      symbol: "DEGEN",
+      amount: "1392.424785087824779911",
+      address: "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed",
+    },
+    tokenOut: {
+      symbol: "USDC",
+      amount: "9.915288",
+      address: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
+    },
+  });
+});
+
 // https://arbiscan.io/tx/0xb2c05194e4ec9ae0f82098ec82a606df544e87c8d6b7726bbb4b1dcc023cb9d7
 test("parse a gasless swap on on Arbitrum (ARB for ETH)", async () => {
   const publicClient = createPublicClient({