fix(virtual): support default imports with Node16 and NodeNext

packages/virtual/package.json

@@ -16,8 +16,14 @@
   "main": "./dist/cjs/index.js",
   "module": "./dist/es/index.js",
   "exports": {
-    "types": "./types/index.d.ts",
-    "import": "./dist/es/index.js",
+    "import": {
+      "types": "./types/index.d.mts",
+      "default": "./dist/es/index.js"
+    },
+    "require": {
+      "types": "./types/index.d.ts",
+      "default": "./dist/cjs/index.js"
+    },
     "default": "./dist/cjs/index.js"
   },
   "engines": {
@@ -35,7 +41,7 @@
     "pretest": "pnpm build",
     "release": "pnpm --workspace-root package:release $(pwd)",
     "test": "vitest --config ../../.config/vitest.config.mts run",
-    "test:ts": "tsc --noEmit"
+    "test:ts": "tsc --noEmit && vitest --config ../../.config/vitest.config.mts run test/types.test.js"
   },
   "files": [
     "dist",

packages/virtual/test/fixtures/types/commonjs.cts

@@ -0,0 +1,7 @@
+import type { Plugin } from 'rollup';
+import virtual, { type RollupVirtualOptions } from '@rollup/plugin-virtual';
+
+const modules: RollupVirtualOptions = { entry: 'export default 42' };
+const plugin: Plugin = virtual(modules);
+
+export default plugin;

packages/virtual/test/fixtures/types/esm.mts

@@ -0,0 +1,15 @@
+import type { Plugin } from 'rollup';
+import virtual, { type RollupVirtualOptions } from '@rollup/plugin-virtual';
+
+const modules: RollupVirtualOptions = { entry: 'export default 42' };
+const plugin: Plugin = virtual(modules);
+
+virtual({});
+
+// @ts-expect-error Virtual module sources must be strings.
+virtual({ entry: 42 });
+
+// @ts-expect-error A module map is required.
+virtual();
+
+export default plugin;

packages/virtual/test/fixtures/types/legacy.ts

@@ -0,0 +1,8 @@
+import type { Plugin } from 'rollup';
+
+import virtual, { type RollupVirtualOptions } from '../../..';
+
+const modules: RollupVirtualOptions = { entry: 'export default 42' };
+const plugin: Plugin = virtual(modules);
+
+export default plugin;

packages/virtual/test/types.test.js

@@ -0,0 +1,41 @@
+const path = require('path');
+
+const ts = require('typescript');
+
+const modes = [
+  ['Node16', ts.ModuleKind.Node16, ts.ModuleResolutionKind.Node16],
+  ['NodeNext', ts.ModuleKind.NodeNext, ts.ModuleResolutionKind.NodeNext]
+];
+
+function diagnostics(fixture, module, moduleResolution) {
+  const program = ts.createProgram([path.join(__dirname, 'fixtures', 'types', fixture)], {
+    esModuleInterop: true,
+    module,
+    moduleResolution,
+    noEmit: true,
+    skipLibCheck: true,
+    strict: true,
+    target: ts.ScriptTarget.ES2019,
+    types: []
+  });
+
+  return ts
+    .getPreEmitDiagnostics(program)
+    .map((diagnostic) => ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n'));
+}
+
+for (const [name, module, moduleResolution] of modes) {
+  test(`supports default imports in ${name} ES modules`, () => {
+    expect(diagnostics('esm.mts', module, moduleResolution)).toEqual([]);
+  });
+
+  test(`supports default imports in ${name} CommonJS modules`, () => {
+    expect(diagnostics('commonjs.cts', module, moduleResolution)).toEqual([]);
+  });
+}
+
+test('supports default imports with legacy Node resolution', () => {
+  expect(diagnostics('legacy.ts', ts.ModuleKind.CommonJS, ts.ModuleResolutionKind.NodeJs)).toEqual(
+    []
+  );
+});

packages/virtual/types/index.d.mts

@@ -0,0 +1,4 @@
+export type { RollupVirtualOptions } from './index.js';
+
+declare const virtual: typeof import('./index.js').default;
+export default virtual;