diff --git a/eslint.config.mjs b/eslint.config.mjs
index b73cc2b8..df9a7bc1 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -41,8 +41,15 @@ const config = tseslint.config(
     },
 
     rules: {
+      'import-x/extensions': ['error', 'ignorePackages'],
       'import-x/no-dynamic-require': 'off',
       'import-x/no-nodejs-modules': 'off',
+      'import-x/no-useless-path-segments': [
+        'error',
+        {
+          noUselessIndex: false,
+        },
+      ],
       'jsdoc/check-tag-names': 'off',
       'jsdoc/no-types': 'off',
       'n/global-require': 'off',
diff --git a/packages/base/src/index.mjs b/packages/base/src/index.mjs
index 98480cf9..aaa00a74 100644
--- a/packages/base/src/index.mjs
+++ b/packages/base/src/index.mjs
@@ -4,11 +4,13 @@ import js from '@eslint/js';
 import importX from 'eslint-plugin-import-x';
 import jsdoc from 'eslint-plugin-jsdoc';
 import prettier from 'eslint-plugin-prettier/recommended';
-// @ts-expect-error - `eslint-plugin-promise` doesn't have TypeScript types.
+// @ts-ignore - `eslint-plugin-promise` doesn't have TypeScript types.
 import promise from 'eslint-plugin-promise';
 import globals from 'globals';
 import { createRequire } from 'module';
 
+import { createConfig } from './utils.mjs';
+
 // TODO: Use import attributes when ESLint supports them.
 const customRequire = createRequire(import.meta.url);
 const environmentRules = customRequire('./environment.json');
@@ -16,406 +18,408 @@ const environmentRules = customRequire('./environment.json');
 /**
  * @type {import('eslint').Linter.Config[]}
  */
-const rules = [
-  // Recommended ESLint configuration.
-  js.configs.recommended,
+const rules = createConfig({
+  name: '@metamask/eslint-config',
 
-  importX.flatConfigs.recommended,
-  jsdoc.configs['flat/recommended-error'],
-  prettier,
-  promise.configs['flat/recommended'],
+  extends: [
+    // Recommended ESLint configuration.
+    js.configs.recommended,
 
-  {
-    name: '@metamask/eslint-config',
+    // Third-party plugin configurations.
+    importX.flatConfigs.recommended,
+    jsdoc.configs['flat/recommended-error'],
+    prettier,
+    promise.configs['flat/recommended'],
+  ],
 
-    languageOptions: {
-      // The `esXXXX` option under `env` is supposed to set the correct
-      // `ecmaVersion` option here, but we've had issues with it being
-      // overridden in the past and therefore set it explicitly.
+  languageOptions: {
+    // The `esXXXX` option under `env` is supposed to set the correct
+    // `ecmaVersion` option here, but we've had issues with it being
+    // overridden in the past and therefore set it explicitly.
+    ecmaVersion: 2022,
+    parserOptions: {
       ecmaVersion: 2022,
-      parserOptions: {
-        ecmaVersion: 2022,
-      },
+    },
 
-      // We want to default to 'script' and only use 'module' explicitly.
-      sourceType: 'script',
+    // We want to default to 'script' and only use 'module' explicitly.
+    sourceType: 'script',
 
-      globals: {
-        ...globals.es2022,
-        ...globals['shared-node-browser'],
-      },
+    globals: {
+      ...globals.es2022,
+      ...globals['shared-node-browser'],
     },
+  },
 
-    rules: {
-      ...environmentRules,
+  rules: {
+    ...environmentRules,
 
-      /* Prettier rules */
-      'prettier/prettier': [
-        'error',
-        {
-          // All of these are defaults except singleQuote and endOfLine, but we specify them
-          // for explicitness
-          endOfLine: 'auto',
-          quoteProps: 'as-needed',
-          singleQuote: true,
-          tabWidth: 2,
-          trailingComma: 'all',
-        },
-        {
-          // Allow consumers to override this Prettier config.
-          // This is the default, but we specify it for the sake of clarity.
-          usePrettierrc: true,
-        },
-      ],
+    /* Prettier rules */
+    'prettier/prettier': [
+      'error',
+      {
+        // All of these are defaults except singleQuote and endOfLine, but we specify them
+        // for explicitness
+        endOfLine: 'auto',
+        quoteProps: 'as-needed',
+        singleQuote: true,
+        tabWidth: 2,
+        trailingComma: 'all',
+      },
+      {
+        // Allow consumers to override this Prettier config.
+        // This is the default, but we specify it for the sake of clarity.
+        usePrettierrc: true,
+      },
+    ],
 
-      curly: ['error', 'all'],
-      'no-tabs': 'error',
+    curly: ['error', 'all'],
+    'no-tabs': 'error',
 
-      /* Core rules */
-      'accessor-pairs': 'error',
-      'array-callback-return': 'error',
-      'block-scoped-var': 'error',
-      camelcase: [
-        'error',
-        {
-          properties: 'never',
-          allow: ['^UNSAFE_'],
-        },
-      ],
-      'consistent-return': 'error',
-      'consistent-this': ['error', 'self'],
-      'default-case': 'error',
-      'default-param-last': 'error',
-      'dot-notation': 'error',
-      eqeqeq: ['error', 'allow-null'],
-      'func-name-matching': 'error',
-      'grouped-accessor-pairs': 'error',
-      'guard-for-in': 'error',
-      'id-denylist': [
-        // This sets this rule to 'error', the rest are the forbidden IDs.
-        'error',
-        // These are basically all useless contractions.
-        'buf',
-        'cat',
-        'err',
-        'cb',
-        'cfg',
-        'hex',
-        'int',
-        'msg',
-        'num',
-        'opt',
-        'sig',
-      ],
-      'id-length': [
-        'error',
-        {
-          min: 2,
-          properties: 'never',
-          exceptionPatterns: ['_', 'a', 'b', 'i', 'j', 'k'],
-        },
-      ],
-      'lines-between-class-members': 'error',
-      'new-cap': [
-        'error',
-        {
-          newIsCap: true,
-          capIsNew: false,
-        },
-      ],
-      'no-alert': 'error',
-      'no-array-constructor': 'error',
-      'no-bitwise': 'error',
-      'no-buffer-constructor': 'error',
-      'no-caller': 'error',
-      'no-constructor-return': 'error',
-      'no-div-regex': 'error',
-      'no-else-return': 'error',
-      'no-empty-function': 'error',
-      'no-eq-null': 'error',
-      'no-eval': 'error',
-      'no-extend-native': 'error',
-      'no-extra-bind': 'error',
-      'no-extra-label': 'error',
-      'no-implicit-coercion': 'error',
-      'no-implicit-globals': 'off',
-      'no-implied-eval': 'error',
-      'no-inner-declarations': ['error', 'functions'],
-      'no-invalid-this': 'error',
-      'no-iterator': 'error',
-      'no-label-var': 'error',
-      'no-labels': [
-        'error',
-        {
-          allowLoop: false,
-          allowSwitch: false,
-        },
-      ],
-      'no-lone-blocks': 'error',
-      'no-lonely-if': 'error',
-      'no-loop-func': 'error',
-      'no-multi-assign': 'error',
-      'no-multi-str': 'error',
-      'no-native-reassign': 'error',
-      'no-negated-condition': 'error',
-      'no-negated-in-lhs': 'error',
-      'no-nested-ternary': 'error',
-      'no-new': 'error',
-      'no-new-func': 'error',
-      'no-new-object': 'error',
-      'no-new-wrappers': 'error',
-      'no-octal-escape': 'error',
-      'no-param-reassign': 'error',
-      'no-plusplus': [
-        'error',
-        {
-          allowForLoopAfterthoughts: true,
-        },
-      ],
-      'no-proto': 'error',
-      'no-restricted-syntax': [
-        'error',
-        {
-          selector: 'WithStatement',
-          message: 'With statements are not allowed',
-        },
-        {
-          selector: `BinaryExpression[operator='in']`,
-          message: 'The "in" operator is not allowed',
-        },
-        // Sequence expressions have potential gotchas with Prettier, and are also
-        // weird!
-        {
-          selector: 'SequenceExpression',
-          message: 'Sequence expressions are not allowed',
-        },
-      ],
-      'no-return-assign': ['error', 'except-parens'],
-      'no-script-url': 'error',
-      'no-self-compare': 'error',
-      'no-shadow': ['error', { builtinGlobals: true }],
-      'no-template-curly-in-string': 'error',
-      'no-throw-literal': 'error',
-      'no-undef-init': 'error',
-      'no-unmodified-loop-condition': 'error',
-      'no-unneeded-ternary': [
-        'error',
-        {
-          defaultAssignment: false,
-        },
-      ],
-      'no-unused-expressions': [
-        'error',
-        {
-          allowShortCircuit: true,
-          allowTernary: true,
-        },
-      ],
-      'no-unused-vars': [
-        'error',
-        {
-          vars: 'all',
-          args: 'all',
-          argsIgnorePattern: '[_]+',
-          ignoreRestSiblings: true,
-        },
-      ],
-      'no-use-before-define': [
-        'error',
-        {
-          functions: false,
-        },
-      ],
-      'no-useless-call': 'error',
-      'no-useless-computed-key': 'error',
-      'no-useless-concat': 'error',
-      'no-useless-constructor': 'error',
-      'no-useless-rename': 'error',
-      'no-useless-return': 'error',
-      'no-var': 'error',
-      'no-void': 'error',
-      'object-shorthand': 'error',
-      'one-var': [
-        'error',
-        {
-          initialized: 'never',
-        },
-      ],
-      'operator-assignment': 'error',
-      'padding-line-between-statements': [
-        'error',
-        {
-          blankLine: 'always',
-          prev: 'directive',
-          next: '*',
-        },
-        {
-          blankLine: 'any',
-          prev: 'directive',
-          next: 'directive',
-        },
-      ],
-      'prefer-const': 'error',
-      'prefer-destructuring': [
-        'error',
-        {
-          VariableDeclarator: {
-            array: false,
-            object: true,
-          },
-          AssignmentExpression: {
-            array: false,
-            object: false,
-          },
-        },
-        {
-          enforceForRenamedProperties: false,
+    /* Core rules */
+    'accessor-pairs': 'error',
+    'array-callback-return': 'error',
+    'block-scoped-var': 'error',
+    camelcase: [
+      'error',
+      {
+        properties: 'never',
+        allow: ['^UNSAFE_'],
+      },
+    ],
+    'consistent-return': 'error',
+    'consistent-this': ['error', 'self'],
+    'default-case': 'error',
+    'default-param-last': 'error',
+    'dot-notation': 'error',
+    eqeqeq: ['error', 'allow-null'],
+    'func-name-matching': 'error',
+    'grouped-accessor-pairs': 'error',
+    'guard-for-in': 'error',
+    'id-denylist': [
+      // This sets this rule to 'error', the rest are the forbidden IDs.
+      'error',
+      // These are basically all useless contractions.
+      'buf',
+      'cat',
+      'err',
+      'cb',
+      'cfg',
+      'hex',
+      'int',
+      'msg',
+      'num',
+      'opt',
+      'sig',
+    ],
+    'id-length': [
+      'error',
+      {
+        min: 2,
+        properties: 'never',
+        exceptionPatterns: ['_', 'a', 'b', 'i', 'j', 'k'],
+      },
+    ],
+    'lines-between-class-members': 'error',
+    'new-cap': [
+      'error',
+      {
+        newIsCap: true,
+        capIsNew: false,
+      },
+    ],
+    'no-alert': 'error',
+    'no-array-constructor': 'error',
+    'no-bitwise': 'error',
+    'no-buffer-constructor': 'error',
+    'no-caller': 'error',
+    'no-constructor-return': 'error',
+    'no-div-regex': 'error',
+    'no-else-return': 'error',
+    'no-empty-function': 'error',
+    'no-eq-null': 'error',
+    'no-eval': 'error',
+    'no-extend-native': 'error',
+    'no-extra-bind': 'error',
+    'no-extra-label': 'error',
+    'no-implicit-coercion': 'error',
+    'no-implicit-globals': 'off',
+    'no-implied-eval': 'error',
+    'no-inner-declarations': ['error', 'functions'],
+    'no-invalid-this': 'error',
+    'no-iterator': 'error',
+    'no-label-var': 'error',
+    'no-labels': [
+      'error',
+      {
+        allowLoop: false,
+        allowSwitch: false,
+      },
+    ],
+    'no-lone-blocks': 'error',
+    'no-lonely-if': 'error',
+    'no-loop-func': 'error',
+    'no-multi-assign': 'error',
+    'no-multi-str': 'error',
+    'no-native-reassign': 'error',
+    'no-negated-condition': 'error',
+    'no-negated-in-lhs': 'error',
+    'no-nested-ternary': 'error',
+    'no-new': 'error',
+    'no-new-func': 'error',
+    'no-new-object': 'error',
+    'no-new-wrappers': 'error',
+    'no-octal-escape': 'error',
+    'no-param-reassign': 'error',
+    'no-plusplus': [
+      'error',
+      {
+        allowForLoopAfterthoughts: true,
+      },
+    ],
+    'no-proto': 'error',
+    'no-restricted-syntax': [
+      'error',
+      {
+        selector: 'WithStatement',
+        message: 'With statements are not allowed',
+      },
+      {
+        selector: `BinaryExpression[operator='in']`,
+        message: 'The "in" operator is not allowed',
+      },
+      // Sequence expressions have potential gotchas with Prettier, and are also
+      // weird!
+      {
+        selector: 'SequenceExpression',
+        message: 'Sequence expressions are not allowed',
+      },
+    ],
+    'no-return-assign': ['error', 'except-parens'],
+    'no-script-url': 'error',
+    'no-self-compare': 'error',
+    'no-shadow': ['error', { builtinGlobals: true }],
+    'no-template-curly-in-string': 'error',
+    'no-throw-literal': 'error',
+    'no-undef-init': 'error',
+    'no-unmodified-loop-condition': 'error',
+    'no-unneeded-ternary': [
+      'error',
+      {
+        defaultAssignment: false,
+      },
+    ],
+    'no-unused-expressions': [
+      'error',
+      {
+        allowShortCircuit: true,
+        allowTernary: true,
+      },
+    ],
+    'no-unused-vars': [
+      'error',
+      {
+        vars: 'all',
+        args: 'all',
+        argsIgnorePattern: '[_]+',
+        ignoreRestSiblings: true,
+      },
+    ],
+    'no-use-before-define': [
+      'error',
+      {
+        functions: false,
+      },
+    ],
+    'no-useless-call': 'error',
+    'no-useless-computed-key': 'error',
+    'no-useless-concat': 'error',
+    'no-useless-constructor': 'error',
+    'no-useless-rename': 'error',
+    'no-useless-return': 'error',
+    'no-var': 'error',
+    'no-void': 'error',
+    'object-shorthand': 'error',
+    'one-var': [
+      'error',
+      {
+        initialized: 'never',
+      },
+    ],
+    'operator-assignment': 'error',
+    'padding-line-between-statements': [
+      'error',
+      {
+        blankLine: 'always',
+        prev: 'directive',
+        next: '*',
+      },
+      {
+        blankLine: 'any',
+        prev: 'directive',
+        next: 'directive',
+      },
+    ],
+    'prefer-const': 'error',
+    'prefer-destructuring': [
+      'error',
+      {
+        VariableDeclarator: {
+          array: false,
+          object: true,
         },
-      ],
-      'prefer-numeric-literals': 'error',
-      'prefer-promise-reject-errors': 'error',
-      'prefer-regex-literals': 'error',
-      'prefer-rest-params': 'error',
-      'prefer-spread': 'error',
-      'prefer-template': 'error',
-      radix: 'error',
-      'require-atomic-updates': 'error',
-      'require-unicode-regexp': 'error',
-      'spaced-comment': [
-        'error',
-        'always',
-        {
-          markers: [
-            'global',
-            'globals',
-            'eslint',
-            'eslint-disable',
-            '*package',
-            '!',
-            ',',
-          ],
-          exceptions: ['=', '-'],
+        AssignmentExpression: {
+          array: false,
+          object: false,
         },
-      ],
-      'symbol-description': 'error',
-      yoda: ['error', 'never'],
+      },
+      {
+        enforceForRenamedProperties: false,
+      },
+    ],
+    'prefer-numeric-literals': 'error',
+    'prefer-promise-reject-errors': 'error',
+    'prefer-regex-literals': 'error',
+    'prefer-rest-params': 'error',
+    'prefer-spread': 'error',
+    'prefer-template': 'error',
+    radix: 'error',
+    'require-atomic-updates': 'error',
+    'require-unicode-regexp': 'error',
+    'spaced-comment': [
+      'error',
+      'always',
+      {
+        markers: [
+          'global',
+          'globals',
+          'eslint',
+          'eslint-disable',
+          '*package',
+          '!',
+          ',',
+        ],
+        exceptions: ['=', '-'],
+      },
+    ],
+    'symbol-description': 'error',
+    yoda: ['error', 'never'],
 
-      /* import plugin rules */
-      'import-x/extensions': [
-        'error',
-        'never',
-        {
-          json: 'always',
-        },
-      ],
-      'import-x/first': 'error',
-      'import-x/newline-after-import': 'error',
-      'import-x/no-absolute-path': 'error',
-      'import-x/no-amd': 'error',
-      'import-x/no-anonymous-default-export': 'error',
-      'import-x/no-duplicates': 'error',
-      'import-x/no-dynamic-require': 'error',
-      'import-x/no-extraneous-dependencies': 'error',
-      'import-x/no-mutable-exports': 'error',
-      'import-x/no-named-as-default': 'error',
-      'import-x/no-named-as-default-member': 'error',
-      'import-x/no-named-default': 'error',
-      'import-x/no-nodejs-modules': 'error',
-      'import-x/no-self-import': 'error',
-      'import-x/no-unassigned-import': 'error',
-      'import-x/no-unresolved': [
-        'error',
-        {
-          commonjs: true,
-        },
-      ],
-      'import-x/no-useless-path-segments': [
-        'error',
-        {
-          commonjs: true,
-          noUselessIndex: true,
-        },
-      ],
-      'import-x/no-webpack-loader-syntax': 'error',
-      'import-x/order': [
-        'error',
-        {
-          // This means that there will always be a newline between the import
-          // groups as defined below.
-          'newlines-between': 'always',
+    /* import plugin rules */
+    'import-x/extensions': [
+      'error',
+      'never',
+      {
+        json: 'always',
+      },
+    ],
+    'import-x/first': 'error',
+    'import-x/newline-after-import': 'error',
+    'import-x/no-absolute-path': 'error',
+    'import-x/no-amd': 'error',
+    'import-x/no-anonymous-default-export': 'error',
+    'import-x/no-duplicates': 'error',
+    'import-x/no-dynamic-require': 'error',
+    'import-x/no-extraneous-dependencies': 'error',
+    'import-x/no-mutable-exports': 'error',
+    'import-x/no-named-as-default': 'error',
+    'import-x/no-named-as-default-member': 'error',
+    'import-x/no-named-default': 'error',
+    'import-x/no-nodejs-modules': 'error',
+    'import-x/no-self-import': 'error',
+    'import-x/no-unassigned-import': 'error',
+    'import-x/no-unresolved': [
+      'error',
+      {
+        commonjs: true,
+      },
+    ],
+    'import-x/no-useless-path-segments': [
+      'error',
+      {
+        commonjs: true,
+        noUselessIndex: true,
+      },
+    ],
+    'import-x/no-webpack-loader-syntax': 'error',
+    'import-x/order': [
+      'error',
+      {
+        // This means that there will always be a newline between the import
+        // groups as defined below.
+        'newlines-between': 'always',
 
-          groups: [
-            // "builtin" is Node.js modules that are built into the runtime, and
-            // "external" is everything else from node_modules.
-            ['builtin', 'external'],
+        groups: [
+          // "builtin" is Node.js modules that are built into the runtime, and
+          // "external" is everything else from node_modules.
+          ['builtin', 'external'],
 
-            // "internal" is unused, but could be used for absolute imports from
-            // the project root.
-            ['internal', 'parent', 'sibling', 'index'],
-          ],
+          // "internal" is unused, but could be used for absolute imports from
+          // the project root.
+          ['internal', 'parent', 'sibling', 'index'],
+        ],
 
-          // Alphabetically sort the imports within each group.
-          alphabetize: {
-            order: 'asc',
-            caseInsensitive: true,
-          },
+        // Alphabetically sort the imports within each group.
+        alphabetize: {
+          order: 'asc',
+          caseInsensitive: true,
         },
-      ],
-      'import-x/unambiguous': 'error',
+      },
+    ],
+    'import-x/unambiguous': 'error',
 
-      /* jsdoc plugin rules */
-      'jsdoc/check-access': 'error',
-      'jsdoc/check-alignment': 'error',
-      'jsdoc/check-line-alignment': 'error',
-      'jsdoc/check-param-names': 'error',
-      'jsdoc/check-property-names': 'error',
-      'jsdoc/check-tag-names': 'error',
-      'jsdoc/check-types': 'error',
-      'jsdoc/check-values': 'error',
-      'jsdoc/empty-tags': 'error',
-      'jsdoc/implements-on-classes': 'error',
-      'jsdoc/match-description': [
-        'error',
-        { tags: { param: true, returns: true } },
-      ],
-      'jsdoc/multiline-blocks': 'error',
-      'jsdoc/no-bad-blocks': 'error',
-      'jsdoc/no-defaults': 'error',
-      'jsdoc/no-multi-asterisks': 'error',
-      'jsdoc/require-asterisk-prefix': 'error',
-      'jsdoc/require-description': 'error',
-      'jsdoc/require-hyphen-before-param-description': [
-        'error',
-        'always',
-        { tags: { returns: 'never', template: 'always', throws: 'never' } },
-      ],
-      'jsdoc/require-jsdoc': 'error',
-      'jsdoc/require-param-name': 'error',
-      'jsdoc/require-param': ['error', { unnamedRootBase: ['options'] }],
-      'jsdoc/require-param-description': 'error',
-      'jsdoc/require-param-type': 'error',
-      'jsdoc/require-property': 'error',
-      'jsdoc/require-property-description': 'error',
-      'jsdoc/require-property-name': 'error',
-      'jsdoc/require-property-type': 'error',
-      'jsdoc/require-returns': 'error',
-      'jsdoc/require-returns-check': 'error',
-      'jsdoc/require-returns-description': 'error',
-      'jsdoc/require-returns-type': 'error',
-      'jsdoc/require-yields': 'error',
-      'jsdoc/require-yields-check': 'error',
-      'jsdoc/tag-lines': [
-        'error',
-        'any',
-        {
-          startLines: 1,
-        },
-      ],
-      'jsdoc/valid-types': 'error',
+    /* jsdoc plugin rules */
+    'jsdoc/check-access': 'error',
+    'jsdoc/check-alignment': 'error',
+    'jsdoc/check-line-alignment': 'error',
+    'jsdoc/check-param-names': 'error',
+    'jsdoc/check-property-names': 'error',
+    'jsdoc/check-tag-names': 'error',
+    'jsdoc/check-types': 'error',
+    'jsdoc/check-values': 'error',
+    'jsdoc/empty-tags': 'error',
+    'jsdoc/implements-on-classes': 'error',
+    'jsdoc/match-description': [
+      'error',
+      { tags: { param: true, returns: true } },
+    ],
+    'jsdoc/multiline-blocks': 'error',
+    'jsdoc/no-bad-blocks': 'error',
+    'jsdoc/no-defaults': 'error',
+    'jsdoc/no-multi-asterisks': 'error',
+    'jsdoc/require-asterisk-prefix': 'error',
+    'jsdoc/require-description': 'error',
+    'jsdoc/require-hyphen-before-param-description': [
+      'error',
+      'always',
+      { tags: { returns: 'never', template: 'always', throws: 'never' } },
+    ],
+    'jsdoc/require-jsdoc': 'error',
+    'jsdoc/require-param-name': 'error',
+    'jsdoc/require-param': ['error', { unnamedRootBase: ['options'] }],
+    'jsdoc/require-param-description': 'error',
+    'jsdoc/require-param-type': 'error',
+    'jsdoc/require-property': 'error',
+    'jsdoc/require-property-description': 'error',
+    'jsdoc/require-property-name': 'error',
+    'jsdoc/require-property-type': 'error',
+    'jsdoc/require-returns': 'error',
+    'jsdoc/require-returns-check': 'error',
+    'jsdoc/require-returns-description': 'error',
+    'jsdoc/require-returns-type': 'error',
+    'jsdoc/require-yields': 'error',
+    'jsdoc/require-yields-check': 'error',
+    'jsdoc/tag-lines': [
+      'error',
+      'any',
+      {
+        startLines: 1,
+      },
+    ],
+    'jsdoc/valid-types': 'error',
 
-      // 'promise/no-multiple-resolved': 'error',
-    },
+    // 'promise/no-multiple-resolved': 'error',
   },
-];
+});
 
+export { createConfig };
 export default rules;
diff --git a/packages/base/src/index.test.mjs b/packages/base/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/base/src/index.test.mjs
+++ b/packages/base/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/base/src/utils.mjs b/packages/base/src/utils.mjs
new file mode 100644
index 00000000..d0632646
--- /dev/null
+++ b/packages/base/src/utils.mjs
@@ -0,0 +1,105 @@
+/**
+ * @typedef {import('eslint').Linter.Config} Config
+ * @typedef {Config & { extends?: Config | Config[] | Config[][] }} ConfigWithExtends
+ */
+
+/**
+ * Get an array from a value. If the value is already an array, it is returned
+ * as is. Otherwise, the value is wrapped in an array.
+ *
+ * @template Type
+ * @param {Type | Type[]} value - The value to convert to an array.
+ * @returns {Type[]} The value as an array.
+ */
+function getArray(value) {
+  return Array.isArray(value) ? value : [value];
+}
+
+/**
+ * Get a config object that extends another config object.
+ *
+ * @param {Config | Config[]} baseConfig - The base config object.
+ * @param {{ files?: string[]; ignores?: string[] }} extension - The extension
+ * object.
+ * @returns {Config | Config[]} The extended config object.
+ */
+function getExtendedConfig(baseConfig, extension) {
+  if (Array.isArray(baseConfig)) {
+    return baseConfig.map((base) => ({ ...base, ...extension }));
+  }
+
+  return { ...baseConfig, ...extension };
+}
+
+/**
+ * Create a config object that extends other configs.
+ *
+ * ESLint 9 removed support for extending arrays of configs, so this function
+ * provides a workaround. It takes an array of config objects, where each object
+ * may have an `extends` property that is an array of other config objects.
+ *
+ * This function is inspired by the `config` function in the `typescript-eslint`
+ * package, but to avoid a dependency on that package, this function is
+ * implemented here.
+ *
+ * @param {ConfigWithExtends | ConfigWithExtends[]} configs - An array of config
+ * objects.
+ * @returns {Config[]} An array of config objects with all `extends` properties
+ * resolved.
+ * @example Basic usage.
+ * import { createConfig } from '@metamask/eslint-config';
+ * import typescript from '@metamask/eslint-config-typescript';
+ *
+ * const configs = createConfig([
+ *   {
+ *     files: ['**\/*.ts'],
+ *     extends: typescript,
+ *   },
+ * ]);
+ *
+ * export default configs;
+ *
+ * @example Multiple extends are supported as well.
+ * import { createConfig } from '@metamask/eslint-config';
+ * import typescript from '@metamask/eslint-config-typescript';
+ * import nodejs from '@metamask/eslint-config-nodejs';
+ *
+ * const configs = createConfig([
+ *   {
+ *     files: ['**\/*.ts'],
+ *     extends: [typescript, nodejs],
+ *   },
+ * ]);
+ *
+ * export default configs;
+ */
+export function createConfig(configs) {
+  const configsArray = getArray(configs);
+
+  return configsArray.flatMap((configWithExtends) => {
+    const { extends: extendsValue, ...originalConfig } = configWithExtends;
+    if (extendsValue === undefined) {
+      return originalConfig;
+    }
+
+    const extension = {
+      ...(originalConfig.files && { files: originalConfig.files }),
+      ...(originalConfig.ignores && { ignores: originalConfig.ignores }),
+    };
+
+    if (Array.isArray(extendsValue)) {
+      if (extendsValue.length === 0) {
+        return originalConfig;
+      }
+
+      return [
+        ...extendsValue.flatMap((baseConfig) =>
+          getExtendedConfig(baseConfig, extension),
+        ),
+        originalConfig,
+      ];
+    }
+
+    return [getExtendedConfig(extendsValue, extension), originalConfig];
+  });
+}
diff --git a/packages/base/src/utils.test.mjs b/packages/base/src/utils.test.mjs
new file mode 100644
index 00000000..fb7b17cc
--- /dev/null
+++ b/packages/base/src/utils.test.mjs
@@ -0,0 +1,68 @@
+import { describe, it, expect } from 'vitest';
+
+import { createConfig } from './utils.mjs';
+
+describe('createConfig', () => {
+  it('returns a config array for a single config', () => {
+    const configs = { files: ['**/*.js'] };
+
+    const result = createConfig(configs);
+    expect(result).toStrictEqual([configs]);
+  });
+
+  it('returns a config array for an array of configs', () => {
+    const configs = [{ files: ['**/*.js'] }, { ignores: ['node_modules'] }];
+
+    const result = createConfig(configs);
+    expect(result).toStrictEqual(configs);
+  });
+
+  it('adds the `files` value to extended configurations', () => {
+    const baseConfig = { rules: {} };
+    const extendedConfig = { extends: [baseConfig], files: ['**/*.js'] };
+
+    const result = createConfig(extendedConfig);
+    expect(result).toStrictEqual([
+      { files: ['**/*.js'], rules: {} },
+      { files: ['**/*.js'] },
+    ]);
+  });
+
+  it('adds the `ignore` value to extended configurations', () => {
+    const baseConfig = { files: ['**/*.js'] };
+    const extendedConfig = { extends: [baseConfig], ignores: ['node_modules'] };
+
+    const result = createConfig(extendedConfig);
+    expect(result).toStrictEqual([
+      { files: ['**/*.js'], ignores: ['node_modules'] },
+      { ignores: ['node_modules'] },
+    ]);
+  });
+
+  it('supports a config object as `extends` value', () => {
+    const baseConfig = { rules: {} };
+    const extendedConfig = { extends: baseConfig, files: ['**/*.js'] };
+
+    const result = createConfig(extendedConfig);
+    expect(result).toStrictEqual([
+      { files: ['**/*.js'], rules: {} },
+      { files: ['**/*.js'] },
+    ]);
+  });
+
+  it('supports a nested config array as `extends` value', () => {
+    const baseConfig = [
+      { rules: { 'foo/bar': 'error' } },
+      { languageOptions: {} },
+    ];
+
+    const extendedConfig = { extends: [baseConfig], files: ['**/*.js'] };
+
+    const result = createConfig(extendedConfig);
+    expect(result).toStrictEqual([
+      { files: ['**/*.js'], rules: { 'foo/bar': 'error' } },
+      { files: ['**/*.js'], languageOptions: {} },
+      { files: ['**/*.js'] },
+    ]);
+  });
+});
diff --git a/packages/browser/src/index.test.mjs b/packages/browser/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/browser/src/index.test.mjs
+++ b/packages/browser/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/commonjs/src/index.test.mjs b/packages/commonjs/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/commonjs/src/index.test.mjs
+++ b/packages/commonjs/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/jest/src/index.test.mjs b/packages/jest/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/jest/src/index.test.mjs
+++ b/packages/jest/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/mocha/src/index.test.mjs b/packages/mocha/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/mocha/src/index.test.mjs
+++ b/packages/mocha/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/nodejs/src/index.test.mjs b/packages/nodejs/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/nodejs/src/index.test.mjs
+++ b/packages/nodejs/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/typescript/src/index.test.mjs b/packages/typescript/src/index.test.mjs
index df0bfdb0..41886b29 100644
--- a/packages/typescript/src/index.test.mjs
+++ b/packages/typescript/src/index.test.mjs
@@ -3,7 +3,7 @@ import globals from 'globals';
 import { resolve } from 'path';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {
diff --git a/packages/vitest/src/index.test.mjs b/packages/vitest/src/index.test.mjs
index 908ffbef..47f24a69 100644
--- a/packages/vitest/src/index.test.mjs
+++ b/packages/vitest/src/index.test.mjs
@@ -1,7 +1,7 @@
 import { ESLint } from 'eslint';
 import { describe, it, expect } from 'vitest';
 
-import config from '.';
+import config from './index.mjs';
 
 describe('index', () => {
   it('is a valid ESLint config', async () => {