feat: support default extensionAlias

e2e/cases/extension-alias/__snapshots__/index.test.ts.snap

@@ -0,0 +1,42 @@
+// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
+
+exports[`resolve.extensionAlias should work 1`] = `
+"\\"use strict\\";
+var __webpack_exports__ = {};
+
+;// CONCATENATED MODULE: ./src/bar.js
+const bar = 'bar';
+
+;// CONCATENATED MODULE: ./src/foo.ts
+const foo = 'foo';
+
+;// CONCATENATED MODULE: ./src/index.ts
+// Relative import paths need explicit file extensions in ECMAScript imports
+// when '--moduleResolution' is 'node16' or 'nodenext'.
+
+
+console.log(foo + bar);
+
+var __webpack_export_target__ = exports;
+for(var i in __webpack_exports__) __webpack_export_target__[i] = __webpack_exports__[i];
+if(__webpack_exports__.__esModule) Object.defineProperty(__webpack_export_target__, '__esModule', { value: true });
+"
+`;
+
+exports[`resolve.extensionAlias should work 2`] = `
+"
+;// CONCATENATED MODULE: ./src/bar.js
+const bar = 'bar';
+
+;// CONCATENATED MODULE: ./src/foo.ts
+const foo = 'foo';
+
+;// CONCATENATED MODULE: ./src/index.ts
+// Relative import paths need explicit file extensions in ECMAScript imports
+// when '--moduleResolution' is 'node16' or 'nodenext'.
+
+
+console.log(foo + bar);
+
+"
+`;

e2e/cases/extension-alias/index.test.ts

@@ -0,0 +1,10 @@
+import { buildAndGetResults } from '@e2e/helper';
+import { expect, test } from 'vitest';
+
+test('resolve.extensionAlias should work', async () => {
+  const fixturePath = __dirname;
+  const { entries } = await buildAndGetResults(fixturePath);
+
+  expect(entries.cjs).toMatchSnapshot();
+  expect(entries.esm).toMatchSnapshot();
+});

e2e/cases/extension-alias/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "extension-alias-test",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module"
+}

e2e/cases/extension-alias/rslib.config.ts

@@ -0,0 +1,14 @@
+import { generateBundleCjsConfig, generateBundleEsmConfig } from '@e2e/helper';
+import { defineConfig } from '@rslib/core';
+
+export default defineConfig({
+  lib: [generateBundleEsmConfig(), generateBundleCjsConfig()],
+  source: {
+    entry: {
+      index: './src/index.ts',
+    },
+    alias: {
+      '@src': 'src',
+    },
+  },
+});

e2e/cases/extension-alias/src/bar.js

@@ -0,0 +1 @@
+export const bar = 'bar';

e2e/cases/extension-alias/src/foo.ts

@@ -0,0 +1 @@
+export const foo = 'foo';

e2e/cases/extension-alias/src/index.ts

@@ -0,0 +1,6 @@
+// Relative import paths need explicit file extensions in ECMAScript imports
+// when '--moduleResolution' is 'node16' or 'nodenext'.
+import { bar } from './bar.js';
+import { foo } from './foo.js';
+
+console.log(foo + bar);

e2e/cases/extension-alias/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "compilerOptions": {
+    "module": "Node16",
+    "moduleResolution": "Node16"
+  },
+  "include": ["src"]
+}

packages/core/src/config.ts

@@ -164,6 +164,16 @@ export async function createInternalRsbuildConfig(): Promise<RsbuildConfig> {
             },
           },
         },
+        // TypeScript-specific behavior: if the extension is ".js" or ".jsx", try replacing it with ".ts" or ".tsx"
+        // see https://github.com/web-infra-dev/rslib/issues/41
+        resolve: {
+          extensionAlias: {
+            '.js': ['.ts', '.tsx', '.js', '.jsx'],
+            '.jsx': ['.tsx', '.jsx'],
+            '.mjs': ['.mts', '.mjs'],
+            '.cjs': ['.cts', '.cjs'],
+          },
+        },
       },
     },
     output: {

packages/core/tests/__snapshots__/config.test.ts.snap

@@ -81,6 +81,28 @@ exports[`Should compose create Rsbuild config correctly > Merge Rsbuild config 1
             "optimization": {
               "moduleIds": "named",
             },
+            "resolve": {
+              "extensionAlias": {
+                ".cjs": [
+                  ".cts",
+                  ".cjs",
+                ],
+                ".js": [
+                  ".ts",
+                  ".tsx",
+                  ".js",
+                  ".jsx",
+                ],
+                ".jsx": [
+                  ".tsx",
+                  ".jsx",
+                ],
+                ".mjs": [
+                  ".mts",
+                  ".mjs",
+                ],
+              },
+            },
           },
         ],
       },
@@ -154,6 +176,28 @@ exports[`Should compose create Rsbuild config correctly > Merge Rsbuild config 1
             "optimization": {
               "moduleIds": "named",
             },
+            "resolve": {
+              "extensionAlias": {
+                ".cjs": [
+                  ".cts",
+                  ".cjs",
+                ],
+                ".js": [
+                  ".ts",
+                  ".tsx",
+                  ".js",
+                  ".jsx",
+                ],
+                ".jsx": [
+                  ".tsx",
+                  ".jsx",
+                ],
+                ".mjs": [
+                  ".mts",
+                  ".mjs",
+                ],
+              },
+            },
           },
         ],
       },
@@ -221,6 +265,28 @@ exports[`Should compose create Rsbuild config correctly > Merge Rsbuild config 1
             "optimization": {
               "moduleIds": "named",
             },
+            "resolve": {
+              "extensionAlias": {
+                ".cjs": [
+                  ".cts",
+                  ".cjs",
+                ],
+                ".js": [
+                  ".ts",
+                  ".tsx",
+                  ".js",
+                  ".jsx",
+                ],
+                ".jsx": [
+                  ".tsx",
+                  ".jsx",
+                ],
+                ".mjs": [
+                  ".mts",
+                  ".mjs",
+                ],
+              },
+            },
           },
         ],
       },

scripts/dictionary.txt

@@ -61,6 +61,7 @@ mjsx
 modularly
 mtsx
 napi
+nodenext
 nolyfill
 ntqry
 onclosetag