feat: add js extension for relative import in bundleless mode

e2e/cases/bundle-false/index.test.ts

@@ -39,3 +39,15 @@ test('single file', async () => {
     ]
   `);
 });
+
+test('auto add extension for relative import', async () => {
+  const fixturePath = join(__dirname, 'relative-import');
+  const { contents } = await buildAndGetResults(fixturePath);
+
+  expect(Object.values(contents.esm)[1]).toContain(
+    'import * as __WEBPACK_EXTERNAL_MODULE__bar_js__ from "./bar.js";',
+  );
+  expect(Object.values(contents.cjs)[1]).toContain(
+    'var external_bar_cjs_namespaceObject = require("./bar.cjs");',
+  );
+});

e2e/cases/bundle-false/relative-import/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "bundle-false-relative-import-test",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module"
+}

e2e/cases/bundle-false/relative-import/rslib.config.ts

@@ -0,0 +1,18 @@
+import { generateBundleCjsConfig, generateBundleEsmConfig } from '@e2e/helper';
+import { defineConfig } from '@rslib/core';
+
+export default defineConfig({
+  lib: [
+    generateBundleEsmConfig(__dirname, {
+      bundle: false,
+    }),
+    generateBundleCjsConfig(__dirname, {
+      bundle: false,
+    }),
+  ],
+  source: {
+    entry: {
+      main: ['./src/**'],
+    },
+  },
+});

e2e/cases/bundle-false/relative-import/src/bar.ts

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

e2e/cases/bundle-false/relative-import/src/index.ts

@@ -0,0 +1,3 @@
+import { bar } from './bar';
+
+export const foo = 'foo' + bar;

e2e/cases/bundle-false/relative-import/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "extends": "@rslib/tsconfig/base",
+  "compilerOptions": {
+    "baseUrl": "./"
+  },
+  "include": ["src"]
+}

e2e/scripts/shared.ts

@@ -55,7 +55,6 @@ type BuildResult = {
 
 export async function getResults(
   rslibConfig: RslibConfig,
-  fixturePath: string,
   type: 'js' | 'dts',
 ): Promise<Omit<BuildResult, 'rspackConfig' | 'rsbuildConfig' | 'isSuccess'>> {
   const files: Record<string, string[]> = {};
@@ -81,7 +80,9 @@ export async function getResults(
       ignore: ['**/*.map'],
     });
 
-    const fileSet = Object.keys(content).filter((file) => regex.test(file));
+    const fileSet = Object.keys(content)
+      .filter((file) => regex.test(file))
+      .sort();
     const filterContent: Record<string, string> = {};
     for (const key of fileSet) {
       if (content[key]) {
@@ -90,7 +91,7 @@ export async function getResults(
     }
 
     if (fileSet.length) {
-      files[libConfig.format!] = fileSet.sort();
+      files[libConfig.format!] = fileSet;
       contents[libConfig.format!] = filterContent;
     }
 
@@ -131,8 +132,8 @@ export async function buildAndGetResults(
     origin: { bundlerConfigs, rsbuildConfig },
   } = await rsbuildInstance.inspectConfig({ verbose: true });
   if (type === 'all') {
-    const jsResults = await getResults(rslibConfig, fixturePath, 'js');
-    const dtsResults = await getResults(rslibConfig, fixturePath, 'dts');
+    const jsResults = await getResults(rslibConfig, 'js');
+    const dtsResults = await getResults(rslibConfig, 'dts');
     return {
       js: {
         contents: jsResults.contents,
@@ -155,7 +156,7 @@ export async function buildAndGetResults(
     };
   }
 
-  const results = await getResults(rslibConfig, fixturePath, type);
+  const results = await getResults(rslibConfig, type);
   return {
     contents: results.contents,
     files: results.files,

packages/core/src/config.ts

@@ -241,6 +241,7 @@ const composeAutoExtensionConfig = (
   pkgJson?: PkgJson,
 ): {
   config: RsbuildConfig;
+  jsExtension: string;
   dtsExtension: string;
 } => {
   const { jsExtension, dtsExtension } = getDefaultExtension({
@@ -257,6 +258,7 @@ const composeAutoExtensionConfig = (
         },
       },
     },
+    jsExtension,
     dtsExtension,
   };
 };
@@ -381,7 +383,10 @@ const composeEntryConfig = async (
   };
 };
 
-const composeBundleConfig = (bundle = true): RsbuildConfig => {
+const composeBundleConfig = (
+  jsExtension: string,
+  bundle = true,
+): RsbuildConfig => {
   if (bundle) return {};
 
   return {
@@ -391,7 +396,14 @@ const composeBundleConfig = (bundle = true): RsbuildConfig => {
           // Issuer is not empty string when the module is imported by another module.
           // Prevent from externalizing entry modules here.
           if (data.contextInfo.issuer) {
-            return callback(null, data.request);
+            // Node.js ECMAScript module loader does no extension searching.
+            // So we add a file extension here when data.request is a relative path
+            return callback(
+              null,
+              data.request[0] === '.'
+                ? `${data.request}${jsExtension}`
+                : data.request,
+            );
           }
           callback();
         },
@@ -474,9 +486,12 @@ async function composeLibRsbuildConfig(
 
   const { format, autoExtension = true, autoExternal = true } = config;
   const formatConfig = composeFormatConfig(format!);
-  const { config: autoExtensionConfig, dtsExtension } =
-    composeAutoExtensionConfig(format!, autoExtension, pkgJson);
-  const bundleConfig = composeBundleConfig(config.bundle);
+  const {
+    config: autoExtensionConfig,
+    jsExtension,
+    dtsExtension,
+  } = composeAutoExtensionConfig(format!, autoExtension, pkgJson);
+  const bundleConfig = composeBundleConfig(jsExtension, config.bundle);
   const targetConfig = composeTargetConfig(config.output?.target);
   const syntaxConfig = composeSyntaxConfig(
     config.output?.syntax,

packages/core/src/utils/helper.ts

@@ -71,7 +71,7 @@ export const nodeBuiltInModules: Array<string | RegExp> = [
   'pnpapi',
 ];
 
-async function calcLongestCommonPath(
+export async function calcLongestCommonPath(
   absPaths: string[],
 ): Promise<string | null> {
   if (absPaths.length === 0) {
@@ -126,4 +126,4 @@ export const readPackageJson = (rootPath: string): undefined | PkgJson => {
 export const isObject = (obj: unknown): obj is Record<string, any> =>
   Object.prototype.toString.call(obj) === '[object Object]';
 
-export { color, calcLongestCommonPath };
+export { color };