feat: add ERC-55 support to ExecutionAddress

packages/types/src/primitive/sszTypes.ts

@@ -1,4 +1,6 @@
 import {ByteVectorType, UintNumberType, UintBigintType, BooleanType} from "@chainsafe/ssz";
+import {ByteArray} from "@chainsafe/ssz/lib/type/byteArray";
+import {toChecksumAddress} from "@lodestar/utils";
 
 export const Boolean = new BooleanType();
 export const Byte = new UintNumberType(1);
@@ -54,11 +56,20 @@ export const Wei = UintBn256;
 export const Root = new ByteVectorType(32);
 export const BlobIndex = UintNum64;
 
+export class ExecutionAddressType extends ByteVectorType {
+    constructor() {
+        super(20);
+    }
+    toJson(value: ByteArray): unknown {
+        return toChecksumAddress(super.toJson(value) as string);
+    }
+};
+
 export const Version = Bytes4;
 export const DomainType = Bytes4;
 export const ForkDigest = Bytes4;
 export const BLSPubkey = Bytes48;
 export const BLSSignature = Bytes96;
 export const Domain = Bytes32;
 export const ParticipationFlags = new UintNumberType(1, {setBitwiseOR: true});
-export const ExecutionAddress = Bytes20;
+export const ExecutionAddress = new ExecutionAddressType();

packages/utils/src/format.ts

@@ -1,4 +1,5 @@
-import {toHexString} from "./bytes.js";
+import {fromHex, toHexString} from "./bytes.js";
+import {keccak256} from "ethereum-cryptography/keccak.js";
 
 /**
  * Format bytes as `0x1234…1234`
@@ -27,3 +28,24 @@ export function truncBytes(root: Uint8Array | string): string {
   const str = typeof root === "string" ? root : toHexString(root);
   return str.slice(0, 14);
 }
+
+/**
+ * Formats an address according to [ERC55](https://eips.ethereum.org/EIPS/eip-55)
+ * 
+ * @param address an hex address
+ * @returns an ERC55 formatted version of `address`
+ */
+export function toChecksumAddress(address: string): string {
+  const rawAddress = address.toLowerCase().startsWith("0x") ? address.slice(2) : address;
+  const bytes = fromHex(rawAddress);
+  const hash = toHexString(keccak256(bytes)).slice(2);
+  let checksumAddress = '0x'
+  for (let i = 0; i < rawAddress.length; i++) {
+    if (parseInt(hash[i], 16) >= 8) {
+      checksumAddress += rawAddress[i].toUpperCase();
+    } else {
+      checksumAddress += rawAddress[i];
+    }
+  }
+  return checksumAddress;
+}

packages/utils/test/unit/format.test.ts

@@ -0,0 +1,11 @@
+import {describe, it, expect} from "vitest";
+import {toChecksumAddress} from "../../src/index.js";
+
+describe("toChecksumAddress", () => {
+  it("should format address as ERC55", () => {
+    expect(toChecksumAddress("52908400098527886E0F7030069857D2E4169EE7")).toBe("0x52908400098527886E0F7030069857D2E4169EE7");
+    expect(toChecksumAddress("0x52908400098527886E0F7030069857D2E4169EE7")).toBe("0x52908400098527886E0F7030069857D2E4169EE7");
+    expect(toChecksumAddress("0xde709f2102306220921060314715629080e2fb77")).toBe("0xdE709F2102306220921060314715629080e2fB77");
+    expect(toChecksumAddress("0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed")).toBe("0x5AAEB6053F3E94C9b9A09F33669435E7Ef1BeAED");
+  });
+});