fix: explicitly changing type if error

tests/client/handlers/vaults.test.ts

@@ -3,6 +3,7 @@ import type { FileSystem } from '@/types';
 import type { VaultId } from '@/ids';
 import type NodeManager from '@/nodes/NodeManager';
 import type {
+  ErrorMessage,
   LogEntryMessage,
   SecretContentMessage,
   VaultListMessage,
@@ -64,7 +65,6 @@ import {
   vaultsSecretsStat,
   vaultsVersion,
 } from '@/client/callers';
-import * as utils from '@/utils';
 import * as keysUtils from '@/keys/utils';
 import * as nodesUtils from '@/nodes/utils';
 import * as vaultsUtils from '@/vaults/utils';
@@ -1371,9 +1371,11 @@ describe('vaultsSecretsMkdir', () => {
     await writer.close();
     for await (const data of response.readable) {
       expect(data.type).toEqual('error');
-      if (data.type !== 'error') utils.never();
-      expect(data.code).toEqual('ENOENT');
-      expect(data.reason).toEqual(dirPath);
+      // TS cannot properly evaluate a type as nested as this, so we use the
+      // as keyword to help it. Inside this block, the type of data is 'error'.
+      const error = data as ErrorMessage;
+      expect(error.code).toEqual('ENOENT');
+      expect(error.reason).toEqual(dirPath);
     }
     await vaultManager.withVaults([vaultId], async (vault) => {
       await vault.readF(async (efs) => {
@@ -1438,9 +1440,12 @@ describe('vaultsSecretsMkdir', () => {
     await writer.close();
     // Check if the operation concluded as expected
     for await (const data of response.readable) {
-      if (data.type !== 'success') {
-        expect(data.code).toEqual('ENOENT');
-        expect(data.reason).toEqual(dirPath3);
+      if (data.type === 'error') {
+        // TS cannot properly evaluate a type as nested as this, so we use the
+        // as keyword to help it. Inside this block, the type of data is 'error'.
+        const error = data as ErrorMessage;
+        expect(error.code).toEqual('ENOENT');
+        expect(error.reason).toEqual(dirPath3);
       }
     }
     await vaultManager.withVaults(
@@ -1474,9 +1479,11 @@ describe('vaultsSecretsMkdir', () => {
     // Check if the operation concluded as expected
     for await (const data of response.readable) {
       expect(data.type).toEqual('error');
-      if (data.type !== 'error') utils.never();
-      expect(data.code).toEqual('EEXIST');
-      expect(data.reason).toEqual(dirPath);
+      // TS cannot properly evaluate a type as nested as this, so we use the
+      // as keyword to help it. Inside this block, the type of data is 'error'.
+      const error = data as ErrorMessage;
+      expect(error.code).toEqual('EEXIST');
+      expect(error.reason).toEqual(dirPath);
     }
     await vaultManager.withVaults([vaultId], async (vault) => {
       await vault.readF(async (efs) => {