fix: require config path or file names

src/index.ts

@@ -27,6 +27,12 @@ export async function loadConfig<
   configParams = [] as unknown as Params,
   fresh = false,
 }: LoadConfigOptions<Params> = {}): Promise<LoadConfigResult<Config>> {
+  if (!path && configFileNames.length === 0) {
+    throw new Error(
+      'Either `path` or at least one `configFileNames` entry must be provided.',
+    );
+  }
+
   const configPath = resolveConfigPath(cwd, path, configFileNames);
 
   if (!configPath) {

src/types.ts

@@ -20,7 +20,7 @@ export type LoadConfigOptions<Params extends unknown[] = []> = {
   path?: string;
   /**
    * Config file names to search in `cwd` when `path` is not provided.
-   * The package-level loader has no built-in framework defaults.
+   * Required when `path` is not provided.
    * @default []
    */
   configFileNames?: string[];

tests/error-handling/index.test.ts

@@ -14,3 +14,15 @@ test('throws when a custom config path cannot be found', async () => {
     `Cannot find config file: ${join(__dirname, 'missing.config.mjs')}`,
   );
 });
+
+test('throws when neither path nor config file names are provided', async () => {
+  await expect(loadConfig({ cwd: __dirname })).rejects.toThrow(
+    'Either `path` or at least one `configFileNames` entry must be provided.',
+  );
+
+  await expect(
+    loadConfig({ cwd: __dirname, configFileNames: [] }),
+  ).rejects.toThrow(
+    'Either `path` or at least one `configFileNames` entry must be provided.',
+  );
+});