From a64f82e8a04ffff167794248dd2d44a584897b61 Mon Sep 17 00:00:00 2001
From: David Walsh <davidwalsh83@gmail.com>
Date: Tue, 27 Sep 2022 10:52:01 -0500
Subject: [PATCH] Avoid using indexes to reference first item in array (#15732)

---
 app/scripts/controllers/preferences.js |  4 ++--
 app/scripts/metamask-controller.js     | 29 ++++++++++++--------------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/app/scripts/controllers/preferences.js b/app/scripts/controllers/preferences.js
index 949c8de8d..520f49179 100644
--- a/app/scripts/controllers/preferences.js
+++ b/app/scripts/controllers/preferences.js
@@ -263,7 +263,7 @@ export default class PreferencesController {
     // If the selected account is no longer valid,
     // select an arbitrary other account:
     if (address === this.getSelectedAddress()) {
-      const selected = Object.keys(identities)[0];
+      const [selected] = Object.keys(identities);
       this.setSelectedAddress(selected);
     }
     return address;
@@ -326,7 +326,7 @@ export default class PreferencesController {
     // select an arbitrary other account:
     let selected = this.getSelectedAddress();
     if (!addresses.includes(selected)) {
-      selected = addresses[0];
+      [selected] = addresses;
       this.setSelectedAddress(selected);
     }
 
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 72efbeb35..bb2001cdb 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -2161,8 +2161,8 @@ export default class MetamaskController extends EventEmitter {
         ethQuery,
       );
 
-      const primaryKeyring =
-        keyringController.getKeyringsByType('HD Key Tree')[0];
+      const [primaryKeyring] =
+        keyringController.getKeyringsByType('HD Key Tree');
       if (!primaryKeyring) {
         throw new Error('MetamaskController - No HD Key Tree found');
       }
@@ -2287,8 +2287,7 @@ export default class MetamaskController extends EventEmitter {
     });
 
     // Accounts
-    const hdKeyring =
-      this.keyringController.getKeyringsByType('HD Key Tree')[0];
+    const [hdKeyring] = this.keyringController.getKeyringsByType('HD Key Tree');
     const simpleKeyPairKeyrings =
       this.keyringController.getKeyringsByType('Simple Key Pair');
     const hdAccounts = await hdKeyring.getAccounts();
@@ -2394,7 +2393,7 @@ export default class MetamaskController extends EventEmitter {
    */
   selectFirstIdentity() {
     const { identities } = this.preferencesController.store.getState();
-    const address = Object.keys(identities)[0];
+    const [address] = Object.keys(identities);
     this.preferencesController.setSelectedAddress(address);
   }
 
@@ -2402,7 +2401,7 @@ export default class MetamaskController extends EventEmitter {
    * Gets the mnemonic of the user's primary keyring.
    */
   getPrimaryKeyringMnemonic() {
-    const keyring = this.keyringController.getKeyringsByType('HD Key Tree')[0];
+    const [keyring] = this.keyringController.getKeyringsByType('HD Key Tree');
     if (!keyring.mnemonic) {
       throw new Error('Primary keyring mnemonic unavailable.');
     }
@@ -2433,9 +2432,7 @@ export default class MetamaskController extends EventEmitter {
           'MetamaskController:getKeyringForDevice - Unknown device',
         );
     }
-    let keyring = await this.keyringController.getKeyringsByType(
-      keyringName,
-    )[0];
+    let [keyring] = await this.keyringController.getKeyringsByType(keyringName);
     if (!keyring) {
       keyring = await this.keyringController.addNewKeyring(keyringName);
     }
@@ -2635,8 +2632,8 @@ export default class MetamaskController extends EventEmitter {
    * @returns {} keyState
    */
   async addNewAccount(accountCount) {
-    const primaryKeyring =
-      this.keyringController.getKeyringsByType('HD Key Tree')[0];
+    const [primaryKeyring] =
+      this.keyringController.getKeyringsByType('HD Key Tree');
     if (!primaryKeyring) {
       throw new Error('MetamaskController - No HD Key Tree found');
     }
@@ -2679,8 +2676,8 @@ export default class MetamaskController extends EventEmitter {
    * encoded as an array of UTF-8 bytes.
    */
   async verifySeedPhrase() {
-    const primaryKeyring =
-      this.keyringController.getKeyringsByType('HD Key Tree')[0];
+    const [primaryKeyring] =
+      this.keyringController.getKeyringsByType('HD Key Tree');
     if (!primaryKeyring) {
       throw new Error('MetamaskController - No HD Key Tree found');
     }
@@ -2804,12 +2801,12 @@ export default class MetamaskController extends EventEmitter {
       'Simple Key Pair',
       [privateKey],
     );
-    const accounts = await keyring.getAccounts();
+    const [firstAccount] = await keyring.getAccounts();
     // update accounts in preferences controller
     const allAccounts = await this.keyringController.getAccounts();
     this.preferencesController.setAddresses(allAccounts);
     // set new account as selected
-    await this.preferencesController.setSelectedAddress(accounts[0]);
+    await this.preferencesController.setSelectedAddress(firstAccount);
   }
 
   // ---------------------------------------------------------------------------
@@ -2875,7 +2872,7 @@ export default class MetamaskController extends EventEmitter {
     if (requestedAccount) {
       account = requestedAccount;
     } else {
-      account = (await this.keyringController.getAccounts())[0];
+      [account] = await this.keyringController.getAccounts();
     }
 
     return this.keyringController.exportAppKeyForAddress(account, subject);