From d6644b316cbef843dc5939d925e2724913be21b6 Mon Sep 17 00:00:00 2001
From: Kyryl R <kyryl.ryabov@gmail.com>
Date: Sat, 6 Jan 2024 18:41:43 +0200
Subject: [PATCH] Added support for passing contract names to the
 getInterfaceID function as well.

---
 CHANGELOG.md                                              | 1 +
 src/index.ts                                              | 6 +++++-
 .../contracts/ERC165Contract.sol                          | 8 ++++++++
 test/index.test.ts                                        | 2 ++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a2c84f..f02511f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,3 +4,4 @@
 
 * Finished the base version of the `getInterfaceID` function.
 * Used `Hardhat` and `solidity-ast` packages to parse the contract and get the interface ID.
+* Added support for passing contract names to the `getInterfaceID` function.
diff --git a/src/index.ts b/src/index.ts
index bb334a9..4a5fe19 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -23,7 +23,11 @@ export async function getInterfaceID(contractName: string) {
   let interfaceID = 0n;
 
   for (const functionDef of allFunctions) {
-    interfaceID = interfaceID ^ BigInt(`0x${functionDef.functionSelector!}`);
+    if (!functionDef.functionSelector) {
+      continue;
+    }
+
+    interfaceID = interfaceID ^ BigInt(`0x${functionDef.functionSelector}`);
   }
 
   return "0x" + interfaceID.toString(16).padStart(8, "0");
diff --git a/test/fixture-projects/hardhat-project-typechain-ethers/contracts/ERC165Contract.sol b/test/fixture-projects/hardhat-project-typechain-ethers/contracts/ERC165Contract.sol
index d2e4d5e..6989ef4 100644
--- a/test/fixture-projects/hardhat-project-typechain-ethers/contracts/ERC165Contract.sol
+++ b/test/fixture-projects/hardhat-project-typechain-ethers/contracts/ERC165Contract.sol
@@ -20,4 +20,12 @@ contract ERC165Contract is ERC165 {
             interfaceId == type(IERC721Enumerable).interfaceId ||
             super.supportsInterface(interfaceId);
     }
+
+    function _version() internal pure returns (string memory) {
+        return "1.0.0";
+    }
+
+    function _author() private pure returns (string memory) {
+        return "0x0";
+    }
 }
diff --git a/test/index.test.ts b/test/index.test.ts
index 2500fe9..88d557a 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -31,6 +31,8 @@ describe("Interface Id Calculation", function () {
     await expect(erc165Contract.supportsInterface(await getInterfaceID("IERC721Enumerable"))).to.be.eventually.true;
     await expect(erc165Contract.supportsInterface(await getInterfaceID("IERC4626"))).to.be.eventually.true;
 
+    expect(await getInterfaceID("IERC165")).to.be.equal(await getInterfaceID("ERC165Contract"));
+
     await expect(erc165Contract.supportsInterface("0xffffffff")).to.be.eventually.false;
   });
 });