fix: name build outputs after the exports map paths

.changeset/esm-output-file-names.md

@@ -0,0 +1,5 @@
+---
+'@strapi/sdk-plugin': patch
+---
+
+Name build output files after the `import` / `require` paths in the package.json exports map instead of hardcoding `index.mjs` / `index.js`, so `"type": "module"` plugins can emit `.cjs` CommonJS and `.js` ESM. `./strapi-admin` and `./strapi-server` now need only one of `import` or `require`, which allows ESM-only plugins. The build warns when an output extension makes Node load it in the wrong module format.

src/__tests__/e2e/build.test.ts

@@ -1,8 +1,11 @@
+import { execFileSync } from 'node:child_process';
 import fs from 'node:fs';
 import path from 'node:path';
 
 import { BUILD_TEST_TIMEOUT_MS, getFixturePath, invokeCLI, withMockedCLI } from './test-utils';
 
+import type { Logger } from '../../cli/commands/utils/logger';
+
 describe('build command', () => {
   it('should validate package.json before building', async () => {
     await withMockedCLI('typescript-plugin', async ({ command }) => {
@@ -115,4 +118,109 @@ describe('build command', () => {
       expect(fs.existsSync(path.join(distTypesDir, 'index.d.ts'))).toBe(true);
     });
   });
+
+  describe('"type": "module" plugin', () => {
+    jest.setTimeout(BUILD_TEST_TIMEOUT_MS);
+
+    const fixturePath = getFixturePath('esm-type-plugin');
+    const distDir = path.join(fixturePath, 'dist');
+    const distServerDir = path.join(distDir, 'server');
+
+    afterEach(() => {
+      fs.rmSync(distDir, { recursive: true, force: true });
+    });
+
+    it('should name output files after the exports map', async () => {
+      const { build } = await import('../../cli/commands/utils/build');
+      const { createLogger } = await import('../../cli/commands/utils/logger');
+      const logger = createLogger({ silent: true, debug: false, timestamp: false });
+
+      await build({
+        cwd: fixturePath,
+        logger,
+        silent: true,
+      });
+
+      expect(fs.readdirSync(distServerDir).sort()).toEqual(['index.cjs', 'index.js']);
+    });
+
+    it('should produce output that Node loads through require and import', async () => {
+      const { build } = await import('../../cli/commands/utils/build');
+      const { createLogger } = await import('../../cli/commands/utils/logger');
+      const logger = createLogger({ silent: true, debug: false, timestamp: false });
+
+      await build({
+        cwd: fixturePath,
+        logger,
+        silent: true,
+      });
+
+      const script = `
+        const assert = require('node:assert');
+        const cjs = require('./dist/server/index.cjs');
+        assert.strictEqual(typeof (cjs.default ?? cjs).register, 'function');
+        import('./dist/server/index.js').then((esm) => {
+          assert.strictEqual(typeof esm.default.register, 'function');
+        });
+      `;
+
+      // Run in a child process from the fixture so Node applies its "type": "module"
+      expect(() =>
+        execFileSync(process.execPath, ['--input-type=commonjs', '-e', script], {
+          cwd: fixturePath,
+          stdio: 'pipe',
+        })
+      ).not.toThrow();
+    });
+
+    it('should warn when require points to a .js file in a "type": "module" package', async () => {
+      const { createViteConfig } = await import('../../cli/commands/utils/build/vite-config');
+      const logger = { warn: jest.fn() } as unknown as Logger;
+
+      await createViteConfig({
+        cwd: fixturePath,
+        logger,
+        bundle: {
+          type: 'server',
+          source: './server/src/index.js',
+          output: { cjs: './dist/server/index.js' },
+        },
+      });
+
+      expect(logger.warn).toHaveBeenCalledWith(expect.stringContaining('Use a ".cjs" extension'));
+    });
+  });
+
+  describe('ESM-only "type": "module" plugin', () => {
+    jest.setTimeout(BUILD_TEST_TIMEOUT_MS);
+
+    const fixturePath = getFixturePath('esm-only-plugin');
+    const distDir = path.join(fixturePath, 'dist');
+
+    afterEach(() => {
+      fs.rmSync(distDir, { recursive: true, force: true });
+    });
+
+    it('should build only the ES output, to the import path', async () => {
+      const { build } = await import('../../cli/commands/utils/build');
+      const { createLogger } = await import('../../cli/commands/utils/logger');
+      const logger = createLogger({ silent: true, debug: false, timestamp: false });
+
+      await build({
+        cwd: fixturePath,
+        logger,
+        silent: true,
+      });
+
+      expect(fs.readdirSync(path.join(distDir, 'server'))).toEqual(['index.js']);
+
+      const script = `import('./dist/server/index.js').then((esm) => {
+        if (typeof esm.default.register !== 'function') process.exit(1);
+      });`;
+
+      expect(() =>
+        execFileSync(process.execPath, ['-e', script], { cwd: fixturePath, stdio: 'pipe' })
+      ).not.toThrow();
+    });
+  });
 });

src/__tests__/e2e/verify.test.ts

@@ -1,4 +1,13 @@
-import { BUILD_TEST_TIMEOUT_MS, ensureFixtureBuilt, invokeCLI, withMockedCLI } from './test-utils';
+import fs from 'node:fs';
+import path from 'node:path';
+
+import {
+  BUILD_TEST_TIMEOUT_MS,
+  ensureFixtureBuilt,
+  getFixturePath,
+  invokeCLI,
+  withMockedCLI,
+} from './test-utils';
 
 describe('verify command', () => {
   it(
@@ -17,6 +26,29 @@ describe('verify command', () => {
     BUILD_TEST_TIMEOUT_MS
   );
 
+  it(
+    'should verify an ESM-only plugin with no require export',
+    async () => {
+      await ensureFixtureBuilt('esm-only-plugin');
+
+      try {
+        await withMockedCLI('esm-only-plugin', async ({ command, mockExit }) => {
+          const cli = await invokeCLI(['verify', '--silent'], command);
+
+          await cli.parseAsync(['node', 'strapi-plugin', 'verify', '--silent']);
+
+          expect(mockExit).not.toHaveBeenCalled();
+        });
+      } finally {
+        fs.rmSync(path.join(getFixturePath('esm-only-plugin'), 'dist'), {
+          recursive: true,
+          force: true,
+        });
+      }
+    },
+    BUILD_TEST_TIMEOUT_MS
+  );
+
   it('should fail for plugin with invalid exports', async () => {
     await withMockedCLI('typescript-plugin', async () => {
       // This test will be more useful when we have fixtures with invalid exports

src/__tests__/fixtures/esm-only-plugin/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@strapi/plugin-esm-only-test",
+  "version": "1.0.0",
+  "description": "ESM-only test plugin (no require export) for E2E testing",
+  "type": "module",
+  "exports": {
+    "./strapi-server": {
+      "source": "./server/src/index.js",
+      "import": "./dist/server/index.js",
+      "default": "./dist/server/index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "strapi-plugin build",
+    "watch": "strapi-plugin watch",
+    "verify": "strapi-plugin verify"
+  },
+  "devDependencies": {
+    "@strapi/strapi": "^5.0.0",
+    "@strapi/sdk-plugin": "^6.0.0"
+  },
+  "peerDependencies": {
+    "@strapi/strapi": "^5.0.0"
+  },
+  "strapi": {
+    "name": "@strapi/plugin-esm-only-test",
+    "displayName": "ESM Only Test Plugin",
+    "description": "ESM-only test plugin (no require export) for E2E testing",
+    "kind": "plugin"
+  }
+}

src/__tests__/fixtures/esm-only-plugin/server/src/index.js

@@ -0,0 +1,8 @@
+export default {
+  register() {
+    // Register phase
+  },
+  bootstrap() {
+    // Bootstrap phase
+  },
+};

src/__tests__/fixtures/esm-type-plugin/package.json

@@ -0,0 +1,36 @@
+{
+  "name": "@strapi/plugin-esm-type-test",
+  "version": "1.0.0",
+  "description": "Test plugin with \"type\": \"module\" for E2E testing",
+  "type": "module",
+  "exports": {
+    "./strapi-server": {
+      "source": "./server/src/index.js",
+      "import": "./dist/server/index.js",
+      "require": "./dist/server/index.cjs",
+      "default": "./dist/server/index.cjs"
+    },
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "strapi-plugin build",
+    "watch": "strapi-plugin watch",
+    "verify": "strapi-plugin verify"
+  },
+  "devDependencies": {
+    "@strapi/strapi": "^5.0.0",
+    "@strapi/sdk-plugin": "^6.0.0"
+  },
+  "peerDependencies": {
+    "@strapi/strapi": "^5.0.0"
+  },
+  "strapi": {
+    "name": "@strapi/plugin-esm-type-test",
+    "displayName": "ESM Type Test Plugin",
+    "description": "Test plugin with \"type\": \"module\" for E2E testing",
+    "kind": "plugin"
+  }
+}

src/__tests__/fixtures/esm-type-plugin/server/src/index.js

@@ -0,0 +1,8 @@
+export default {
+  register() {
+    // Register phase
+  },
+  bootstrap() {
+    // Bootstrap phase
+  },
+};

src/cli/commands/utils/build/index.ts

@@ -105,16 +105,17 @@
       logger.info(`Building ${bundle.type} bundle...`);
     }
 
     const config = await createViteConfig({
       cwd,
       bundle,
       minify,
       sourcemap,
       silent,
+      logger,
     });
 
     const { build: viteBuild } = await import('vite');
     await viteBuild(config);
 
     if (!silent) {
       logger.info(`${bundle.type} bundle built successfully`);