Added BNLike input type for chain IDs in toChecksumAddress() and isValidChecksumAddress(), expanded tests

Author: holgerd77

src/account.ts

@@ -1,7 +1,7 @@
 import assert from 'assert'
 import BN from 'bn.js'
 import * as rlp from 'rlp'
-import { stripHexPrefix } from 'ethjs-util'
+import { isHexString, stripHexPrefix } from 'ethjs-util'
 import { KECCAK256_RLP, KECCAK256_NULL } from './constants'
 import { zeros, bufferToHex, toBuffer } from './bytes'
 import { keccak, keccak256, keccakFromString, rlphash } from './hash'
@@ -137,11 +137,23 @@ export const isValidAddress = function(hexAddress: string): boolean {
  * WARNING: Checksums with and without the chainId will differ. As of 2019-06-26, the most commonly
  * used variation in Ethereum was without the chainId. This may change in the future.
  */
-export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: number): string {
+export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: BNLike): string {
   assertIsHexString(hexAddress)
+  if (typeof eip1191ChainId === 'string' && !isHexString(eip1191ChainId)) {
+    throw new Error(`A chainId string must be provided with a 0x-prefix, given: ${eip1191ChainId}`)
+  }
   const address = stripHexPrefix(hexAddress).toLowerCase()
 
-  const prefix = eip1191ChainId !== undefined ? eip1191ChainId.toString() + '0x' : ''
+  let prefix = ''
+  if (eip1191ChainId) {
+    // Performance optimization
+    if (typeof eip1191ChainId === 'number' && Number.isSafeInteger(eip1191ChainId)) {
+      prefix = eip1191ChainId.toString()
+    } else {
+      prefix = new BN(toBuffer(eip1191ChainId)).toString()
+    }
+    prefix += '0x'
+  }
 
   const hash = keccakFromString(prefix + address).toString('hex')
   let ret = '0x'
@@ -164,7 +176,7 @@ export const toChecksumAddress = function(hexAddress: string, eip1191ChainId?: n
  */
 export const isValidChecksumAddress = function(
   hexAddress: string,
-  eip1191ChainId?: number
+  eip1191ChainId?: BNLike
 ): boolean {
   return isValidAddress(hexAddress) && toChecksumAddress(hexAddress, eip1191ChainId) === hexAddress
 }

test/account.spec.ts

@@ -602,9 +602,27 @@ describe('.toChecksumAddress()', function() {
       for (const [chainId, addresses] of Object.entries(eip1191ChecksummAddresses)) {
         for (const addr of addresses) {
           assert.equal(toChecksumAddress(addr.toLowerCase(), Number(chainId)), addr)
+          assert.equal(toChecksumAddress(addr.toLowerCase(), Buffer.from([chainId])), addr)
+          assert.equal(toChecksumAddress(addr.toLowerCase(), new BN(chainId)), addr)
+          assert.equal(
+            toChecksumAddress(addr.toLowerCase(), '0x' + Buffer.from([chainId]).toString('hex')),
+            addr
+          )
         }
       }
     })
+    it('Should encode large chain ids greater than MAX_INTEGER correctly', function() {
+      const addr = '0x88021160C5C792225E4E5452585947470010289D'
+      const chainIDBuffer = Buffer.from('796f6c6f763378', 'hex')
+      assert.equal(toChecksumAddress(addr.toLowerCase(), chainIDBuffer), addr)
+      assert.equal(toChecksumAddress(addr.toLowerCase(), new BN(chainIDBuffer)), addr)
+      assert.equal(
+        toChecksumAddress(addr.toLowerCase(), '0x' + chainIDBuffer.toString('hex')),
+        addr
+      )
+      const chainIDNumber = parseInt(chainIDBuffer.toString('hex'), 16)
+      assert.equal(toChecksumAddress(addr.toLowerCase(), chainIDNumber), addr)
+    })
   })
 
   describe('input format', function() {
@@ -613,6 +631,11 @@ describe('.toChecksumAddress()', function() {
         toChecksumAddress('52908400098527886E0F7030069857D2E4169EE7'.toLowerCase())
       })
     })
+    it('Should throw when the chainId is not hex-prefixed', function() {
+      assert.throws(function() {
+        toChecksumAddress('0xde709f2102306220921060314715629080e2fb77', '1234')
+      })
+    })
   })
 })
 
@@ -633,6 +656,12 @@ describe('.isValidChecksumAddress()', function() {
       for (const [chainId, addresses] of Object.entries(eip1191ChecksummAddresses)) {
         for (const addr of addresses) {
           assert.equal(isValidChecksumAddress(addr, Number(chainId)), true)
+          assert.equal(isValidChecksumAddress(addr, Buffer.from([chainId])), true)
+          assert.equal(isValidChecksumAddress(addr, new BN(chainId)), true)
+          assert.equal(
+            isValidChecksumAddress(addr, '0x' + Buffer.from([chainId]).toString('hex')),
+            true
+          )
         }
       }
     })