fix: file extension is not added to imported files w/ NodeNext - lint fix, tests

Author: rkday-pro

packages/core/src/utils/tsconfig.test.ts

@@ -0,0 +1,67 @@
+import { describe, expect, it } from 'vitest';
+
+import type { Tsconfig } from '../types';
+import { getImportExtension } from './tsconfig';
+
+describe('getImportExtension', () => {
+  it('strips a .ts file extension when no tsconfig is provided', () => {
+    expect(getImportExtension('.ts')).toBe('');
+    expect(getImportExtension('.gen.ts')).toBe('.gen');
+  });
+
+  it('preserves non-.ts file extensions when no tsconfig is provided', () => {
+    expect(getImportExtension('.mjs')).toBe('.mjs');
+  });
+
+  it('keeps the file extension as-is when allowImportingTsExtensions is true', () => {
+    const tsconfig: Tsconfig = {
+      compilerOptions: { allowImportingTsExtensions: true },
+    };
+    expect(getImportExtension('.gen.ts', tsconfig)).toBe('.gen.ts');
+    expect(getImportExtension('.ts', tsconfig)).toBe('.ts');
+  });
+
+  it('rewrites .ts to .js when module is NodeNext', () => {
+    const tsconfig: Tsconfig = {
+      compilerOptions: { module: 'NodeNext' },
+    };
+    expect(getImportExtension('.ts', tsconfig)).toBe('.js');
+    expect(getImportExtension('.gen.ts', tsconfig)).toBe('.gen.js');
+  });
+
+  it('rewrites .ts to .js when moduleResolution is Node16', () => {
+    const tsconfig: Tsconfig = {
+      compilerOptions: { moduleResolution: 'Node16' },
+    };
+    expect(getImportExtension('.ts', tsconfig)).toBe('.js');
+  });
+
+  it('matches NodeNext/Node16 case-insensitively', () => {
+    expect(
+      getImportExtension('.ts', { compilerOptions: { module: 'nodenext' } }),
+    ).toBe('.js');
+    expect(
+      getImportExtension('.ts', {
+        compilerOptions: { moduleResolution: 'node16' },
+      }),
+    ).toBe('.js');
+  });
+
+  it('prefers allowImportingTsExtensions over NodeNext rewrites', () => {
+    const tsconfig: Tsconfig = {
+      compilerOptions: {
+        module: 'NodeNext',
+        allowImportingTsExtensions: true,
+      },
+    };
+    expect(getImportExtension('.gen.ts', tsconfig)).toBe('.gen.ts');
+  });
+
+  it('falls back to stripping .ts for other module settings', () => {
+    const tsconfig: Tsconfig = {
+      compilerOptions: { module: 'ESNext' },
+    };
+    expect(getImportExtension('.ts', tsconfig)).toBe('');
+    expect(getImportExtension('.gen.ts', tsconfig)).toBe('.gen');
+  });
+});

packages/core/src/utils/tsconfig.ts

@@ -13,7 +13,7 @@ export function isSyntheticDefaultImportsAllow(config?: Tsconfig) {
 
 const NODE_NEXT_MODULES = new Set(['nodenext', 'node16']);
 
-const NODE_NEXT_EXTENSION_MAP: ReadonlyArray<readonly [string, string]> = [
+const NODE_NEXT_EXTENSION_MAP: readonly (readonly [string, string])[] = [
   ['.tsx', '.jsx'],
   ['.mts', '.mjs'],
   ['.cts', '.cjs'],