Warn when a story file contains no exported stories

.changeset/fiery-facts-pick.md

@@ -0,0 +1,5 @@
+---
+"@ladle/react": patch
+---
+
+Ladle now prints a warning when it encounters a story file that contains no exported stories.

packages/ladle/lib/cli/vite-plugin/parse/get-entry-data.js

@@ -69,5 +69,8 @@ export const getSingleEntry = async (entry) => {
     return 0;
   });
   debug(result);
+  if (result.stories.length === 0) {
+    console.warn(`Warning: Found no exported stories at ${entry}`);
+  }
   return result;
 };

packages/ladle/tests/fixtures/no-export.stories.tsx

@@ -0,0 +1,10 @@
+import * as React from "react";
+import type { Story } from "@ladle/react";
+
+const Cat: Story = () => {
+  return <h1>Cat</h1>;
+};
+
+const Dog: Story = () => {
+  return <h1>Dog</h1>;
+};

packages/ladle/tests/parse/get-entry-data.test.ts

@@ -1,4 +1,4 @@
-import { test, expect } from "vitest";
+import { test, expect, vi } from "vitest";
 import { getSingleEntry } from "../../lib/cli/vite-plugin/parse/get-entry-data.js";
 
 test("Single file with two stories", async () => {
@@ -54,3 +54,12 @@ test("Extract and merge story meta", async () => {
   );
   expect(entryData).toMatchSnapshot();
 });
+
+test("Warns when a stories file has no exported stories", async () => {
+  const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+  await getSingleEntry("tests/fixtures/no-export.stories.tsx");
+  expect(warn).toHaveBeenCalledWith(
+    expect.stringContaining("Warning: Found no exported stories"),
+  );
+  warn.mockRestore();
+});