Added support for passing contract names to the getInterfaceID functi…

…on as well.

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.

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");

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";
+    }
 }

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;
   });
 });