feat: add checksum addresses

__tests__/utils/address.test.ts

@@ -1,4 +1,9 @@
-import { addAddressPadding, validateAndParseAddress } from '../../src/utils/address';
+import {
+  addAddressPadding,
+  getChecksumAddress,
+  validateAndParseAddress,
+  validateChecksumAddress,
+} from '../../src/utils/address';
 // import { addHexPrefix, removeHexPrefix } from '../../src/utils/encode';
 
 describe('validateAndParseAddress', () => {
@@ -14,3 +19,27 @@ describe('validateAndParseAddress', () => {
     return expect(validateAndParseAddress(addr)).toEqual(`${addAddressPadding(addr)}`);
   });
 });
+
+describe('address checksums', () => {
+  test('should be able to calculate checksum address', () => {
+    const checksumAddress = getChecksumAddress(
+      '0x2fd23d9182193775423497fc0c472e156c57c69e4089a1967fb288a2d84e914'
+    );
+    expect(checksumAddress).toEqual(
+      '0x02FD23D9182193775423497Fc0c472E156C57C69E4089a1967fb288a2D84e914'
+    );
+  });
+  test('should be able to verify checksum address', () => {
+    const isValid = validateChecksumAddress(
+      '0x02FD23D9182193775423497Fc0c472E156C57C69E4089a1967fb288a2D84e914'
+    );
+    expect(isValid).toEqual(true);
+  });
+  test('calculated checksum address should validate', () => {
+    const checksumAddress = getChecksumAddress(
+      '0x26cb0b500d175111341fabb53bf7fa4f5a0b8c5cbb31896cec1e8383a5edda8'
+    );
+    const isValid = validateChecksumAddress(checksumAddress);
+    expect(isValid).toEqual(true);
+  });
+});

package.json

@@ -61,6 +61,7 @@
     "typescript": "^4.4.4"
   },
   "dependencies": {
+    "@ethersproject/bytes": "^5.6.1",
     "axios": "^0.23.0",
     "bn.js": "^5.2.0",
     "elliptic": "^6.5.4",

src/utils/address.ts

@@ -1,16 +1,16 @@
+/* eslint-disable no-bitwise */
+import { arrayify } from '@ethersproject/bytes';
+
 import { MASK_251, ZERO } from '../constants';
 import { addHexPrefix, removeHexPrefix } from './encode';
-import { assertInRange } from './number';
+import { pedersen } from './hash';
+import { BigNumberish, assertInRange, toBN, toHex } from './number';
 
-export function addAddressPadding(address: string): string {
-  return addHexPrefix(removeHexPrefix(address).padStart(64, '0'));
+export function addAddressPadding(address: BigNumberish): string {
+  return addHexPrefix(removeHexPrefix(toHex(toBN(address))).padStart(64, '0'));
 }
 
-export function validateAndParseAddress(address: string): string {
-  if (typeof address !== 'string') {
-    throw new Error('Invalid Address Type');
-  }
-
+export function validateAndParseAddress(address: BigNumberish): string {
   assertInRange(address, ZERO, MASK_251, 'Starknet Address');
 
   const result = addAddressPadding(address);
@@ -21,3 +21,23 @@ export function validateAndParseAddress(address: string): string {
 
   return result;
 }
+
+export const getChecksumAddress = (address: BigNumberish): string => {
+  const chars = removeHexPrefix(validateAndParseAddress(address)).toLowerCase().split('');
+  const hashed = arrayify(pedersen([0, address]), { hexPad: 'left' }); // as the hash will be 251 bits (63 chars) we need to pad it to 64 chars without changing the number value ("left")
+
+  for (let i = 0; i < chars.length; i += 2) {
+    if (hashed[i >> 1] >> 4 >= 8) {
+      chars[i] = chars[i].toUpperCase();
+    }
+    if ((hashed[i >> 1] & 0x0f) >= 8) {
+      chars[i + 1] = chars[i + 1].toUpperCase();
+    }
+  }
+
+  return addHexPrefix(chars.join(''));
+};
+
+export const validateChecksumAddress = (address: string): boolean => {
+  return getChecksumAddress(address) === address;
+};