chore: allow hd path for the privateKey class

packages/sdk-ts/src/core/accounts/PrivateKey.spec.ts

@@ -1,9 +1,13 @@
 import { generateArbitrarySignDoc } from '../tx'
 import { PrivateKey } from './PrivateKey'
 
-const pk = 'f9db9bf330e23cb7839039e944adef6e9df447b90b503d5b4464c90bea9022f3'
+const pk = process.env.TEST_PRIVATE_KEY as string
 const seedPhase = process.env.TEST_SEED_PHASE as string
 
+if (!pk || !seedPhase) {
+  throw new Error('TEST_PRIVATE_KEY or TEST_SEED_PHASE is not set')
+}
+
 describe('PrivateKey', () => {
   it('returns the correct address derived from a mnemonic', () => {
     const privateKey = PrivateKey.fromMnemonic(seedPhase)

packages/sdk-ts/src/core/accounts/PrivateKey.ts

@@ -1,12 +1,15 @@
 import { generateMnemonic } from 'bip39'
-import { Wallet } from 'ethers'
+import { Wallet, HDNodeWallet } from 'ethers'
 import secp256k1 from 'secp256k1'
 import keccak256 from 'keccak256'
 import { PublicKey } from './PublicKey'
 import { Address } from './Address'
 import * as BytesUtils from '@ethersproject/bytes'
 import { signTypedData, SignTypedDataVersion } from '@metamask/eth-sig-util'
-import { recoverTypedSignaturePubKey } from '../../utils'
+import {
+  DEFAULT_DERIVATION_PATH,
+  recoverTypedSignaturePubKey,
+} from '../../utils'
 import {
   CosmosTxV1Beta1Tx,
   InjectiveTypesV1Beta1TxExt,
@@ -49,8 +52,13 @@ export class PrivateKey {
    * @param {string|undefined} path the HD path that follows the BIP32 standard (optional)
    * @returns {PrivateKey} Initialized PrivateKey object
    */
-  static fromMnemonic(words: string): PrivateKey {
-    return new PrivateKey(new Wallet(Wallet.fromPhrase(words).signingKey))
+  static fromMnemonic(
+    words: string,
+    path: string = DEFAULT_DERIVATION_PATH,
+  ): PrivateKey {
+    const hdNodeWallet = HDNodeWallet.fromPhrase(words, undefined, path)
+
+    return new PrivateKey(new Wallet(hdNodeWallet.privateKey))
   }
 
   /**