Update

src/index.ts

@@ -56,11 +56,18 @@ export interface LocalRuleOptions {
 
 export type RuleOptions = Rules & Partial<LocalRuleOptions>;
 
+export interface CustomRule {
+  rule: () => Promise<{
+    default: Rule.RuleModule | ESLintUtils.RuleModule<string, unknown[]>;
+  }>;
+  options?: RuleLevel;
+}
+
 /**
  * ESLint Configuration.
  * @see [ESLint Configuration](https://eslint.org/docs/latest/user-guide/configuring/)
  */
-type Config = Omit<ESLintConfig, 'rules'> & {
+export type InputConfig = Omit<ESLintConfig, 'rules'> & {
   /**
    * Rules.
    * @see [Rules](https://eslint.org/docs/latest/user-guide/configuring/rules)
@@ -68,24 +75,13 @@ type Config = Omit<ESLintConfig, 'rules'> & {
   rules?: RuleOptions;
 
   /**
+   * Glob pattern to find paths to custom rule files in JavaScript or TypeScript.
+   * Note this must be a string literal or an array of string literals since
+   * this is statically analyzed.
    */
-  customRules?: {
-    rule: () => Promise<{
-      default: Rule.RuleModule | ESLintUtils.RuleModule<string, unknown[]>;
-    }>;
-    options?: RuleLevel;
-  }[];
+  customRuleFiles?: string | string[];
 };
 
-export function defineCustomRule<Options extends readonly unknown[]>(
-  rule: () => Promise<{
-    default: Rule.RuleModule | ESLintUtils.RuleModule<string, Options>;
-  }>,
-  options?: Options,
-) {
-  return { rule, options };
-}
-
 /**
  * Returns a ESLint config object.
  *
@@ -104,15 +100,17 @@ export function defineCustomRule<Options extends readonly unknown[]>(
  * Non bundled:
  * 1. [`graphql`](https://the-guild.dev/graphql/eslint/rules)
  */
-export function extendConfig({
-  plugins = [],
-  settings,
-  rules,
-  extends: _extends,
-  overrides,
-  customRules,
-  ...rest
-}: Config = {}): ESLintConfig {
+export function extendConfig(of: InputConfig = {}): ESLintConfig {
+  const {
+    plugins = [],
+    settings,
+    rules,
+    extends: _extends,
+    overrides,
+    customRuleFiles,
+    ...rest
+  } = of;
+
   const hasReact = plugins.includes('react');
   const hasReactRefresh = plugins.includes('react-refresh');
   const hasUnicorn = plugins.includes('unicorn');
@@ -129,7 +127,7 @@ export function extendConfig({
     fs.mkdirSync(ruleDir, { recursive: true });
   }
 
-  const result: Config = {
+  const result: InputConfig = {
     root: true,
     parser: '@typescript-eslint/parser',
     plugins: unique('@typescript-eslint', 'import', 'rules', plugins),