rolldown · graphite-app · Feb 25, 2026 · Feb 25, 2026
diff --git a/crates/rolldown/src/utils/parse_to_ecma_ast.rs b/crates/rolldown/src/utils/parse_to_ecma_ast.rs
@@ -3,7 +3,8 @@ use std::{borrow::Cow, path::Path};
 use json_escape_simd::escape;
 use oxc::{semantic::Scoping, span::SourceType as OxcSourceType};
 use rolldown_common::{
-  ModuleType, NormalizedBundlerOptions, RUNTIME_MODULE_KEY, StrOrBytes, json_value_to_ecma_ast,
+  ModuleDefFormat, ModuleType, NormalizedBundlerOptions, RUNTIME_MODULE_KEY, StrOrBytes,
+  json_value_to_ecma_ast,
 };
 use rolldown_ecmascript::{EcmaAst, EcmaCompiler};
 use rolldown_error::{BuildDiagnostic, BuildResult};
@@ -16,14 +17,22 @@ use super::pre_process_ecma_ast::PreProcessEcmaAst;
 use crate::types::{module_factory::CreateModuleContext, oxc_parse_type::OxcParseType};
 
 #[inline]
-fn pure_esm_js_oxc_source_type() -> OxcSourceType {
-  let pure_esm_js = OxcSourceType::default().with_module(true);
-  debug_assert!(pure_esm_js.is_javascript());
-  debug_assert!(!pure_esm_js.is_jsx());
-  debug_assert!(pure_esm_js.is_module());
-  debug_assert!(pure_esm_js.is_strict());
-
-  pure_esm_js
+fn pure_esm_js_oxc_source_type(module_def_format: ModuleDefFormat) -> OxcSourceType {
+  let default_source_type = OxcSourceType::default();
+  debug_assert!(default_source_type.is_javascript());
+  debug_assert!(!default_source_type.is_jsx());
+  match module_def_format {
+    ModuleDefFormat::Cjs | ModuleDefFormat::Cts | ModuleDefFormat::CjsPackageJson => {
+      default_source_type.with_commonjs(true)
+    }
+    ModuleDefFormat::EsmMjs | ModuleDefFormat::EsmMts | ModuleDefFormat::EsmPackageJson => {
+      default_source_type.with_module(true)
+    }
+    ModuleDefFormat::Unknown => {
+      // treat unknown format as ESM for now: https://github.com/rolldown/rolldown/issues/7009
+      default_source_type.with_module(true)
+    }
+  }
 }
 
 pub struct ParseToEcmaAstResult {
@@ -57,7 +66,7 @@ pub async fn parse_to_ecma_ast(
     pre_process_source(path, source, module_type, options)?;
 
   let oxc_source_type = {
-    let default = pure_esm_js_oxc_source_type();
+    let default = pure_esm_js_oxc_source_type(resolved_id.module_def_format);
     match parsed_type {
       OxcParseType::Js => default,
       OxcParseType::Jsx => default.with_jsx(!options.transform_options.is_jsx_disabled()),

diff --git a/crates/rolldown/tests/rolldown/issues/4289/_config.json b/crates/rolldown/tests/rolldown/issues/4289/_config.json
@@ -1,5 +1,6 @@
 {
   "config": {
+    "platform": "node",
     "external": ["node:assert"]
   },
   "configVariants": [

diff --git a/crates/rolldown/tests/rolldown/issues/4289/artifacts.snap b/crates/rolldown/tests/rolldown/issues/4289/artifacts.snap
@@ -17,11 +17,13 @@ var require_lib = /* @__PURE__ */ __commonJSMin(((exports) => {
 //#endregion
 export default require_lib();
 
+export {  };
 ```
 
 ## main.js
 
 ```js
+import { createRequire } from "node:module";
 import nodeAssert from "node:assert";
 
 // HIDDEN [\0rolldown/runtime.js]
@@ -47,11 +49,12 @@ main();
 //#endregion
 //#region node-mode-by-cjs-extension.cjs
 var require_node_mode_by_cjs_extension = /* @__PURE__ */ __commonJSMin(((exports, module) => {
+	const nodeAssert$1 = __require("node:assert");
 	async function main() {
 		const exports$1 = await import("./lib.js").then((m) => /* @__PURE__ */ __toESM(m.default, 1));
-		nodeAssert.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
-		nodeAssert.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
-		nodeAssert.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
+		nodeAssert$1.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
+		nodeAssert$1.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
+		nodeAssert$1.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
 	}
 	main();
 	module.exports = {};
@@ -119,11 +122,12 @@ main();
 //#endregion
 //#region node-mode-by-cjs-extension.cjs
 var require_node_mode_by_cjs_extension = /* @__PURE__ */ __commonJSMin(((exports, module) => {
+	const nodeAssert = require("node:assert");
 	async function main() {
 		const exports$1 = await Promise.resolve().then(() => /* @__PURE__ */ __toESM(require("./lib.js").default, 1));
-		node_assert.default.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
-		node_assert.default.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
-		node_assert.default.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
+		nodeAssert.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
+		nodeAssert.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
+		nodeAssert.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
 	}
 	main();
 	module.exports = {};
@@ -144,6 +148,7 @@ exports.__commonJSMin = __commonJSMin;
 ### main.js
 
 ```js
+import { createRequire } from "node:module";
 import nodeAssert from "node:assert";
 
 // HIDDEN [\0rolldown/runtime.js]
@@ -176,11 +181,12 @@ main();
 //#endregion
 //#region node-mode-by-cjs-extension.cjs
 var require_node_mode_by_cjs_extension = /* @__PURE__ */ __commonJSMin(((exports, module) => {
+	const nodeAssert$1 = __require("node:assert");
 	async function main() {
 		const exports$1 = await Promise.resolve().then(() => /* @__PURE__ */ __toESM(require_lib(), 1));
-		nodeAssert.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
-		nodeAssert.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
-		nodeAssert.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
+		nodeAssert$1.deepEqual(Object.keys(exports$1).sort(), ["default", "parse"]);
+		nodeAssert$1.strictEqual(exports$1.parse, "parse", "Expected export exists and is correct");
+		nodeAssert$1.strictEqual(exports$1.default.parse, "parse", "Target has __esModule, but this file triggered node compat mode");
 	}
 	main();
 	module.exports = {};
@@ -191,4 +197,5 @@ var require_node_mode_by_cjs_extension = /* @__PURE__ */ __commonJSMin(((exports
 var import_node_mode_by_cjs_extension = require_node_mode_by_cjs_extension();
 
 //#endregion
+export {  };
 ```
diff --git a/crates/rolldown/tests/rolldown/issues/4289/node-mode-by-cjs-extension.cjs b/crates/rolldown/tests/rolldown/issues/4289/node-mode-by-cjs-extension.cjs
@@ -1,4 +1,4 @@
-import nodeAssert from 'node:assert';
+const nodeAssert = require('node:assert');
 
 async function main() {
   const exports = await import('./lib.js');

diff --git a/crates/rolldown/tests/rolldown/issues/7009/cjs/_config.json b/crates/rolldown/tests/rolldown/issues/7009/cjs/_config.json
@@ -0,0 +1,12 @@
+{
+  "config": {
+    "input": [
+      {
+        "name": "main",
+        "import": "./index.cjs"
+      }
+    ],
+    "format": "cjs"
+  },
+  "expectExecuted": false
+}
diff --git a/crates/rolldown/tests/rolldown/issues/7009/cjs/artifacts.snap b/crates/rolldown/tests/rolldown/issues/7009/cjs/artifacts.snap
@@ -0,0 +1,17 @@
+---
+source: crates/rolldown_testing/src/integration_test.rs
+---
+# Assets
+
+## main.js
+
+```js
+
+//#region index.cjs
+exports.foo = function a() {
+	return "foo";
+};
+arguments = 1;
+
+//#endregion
+```
diff --git a/crates/rolldown/tests/rolldown/issues/7009/cjs/index.cjs b/crates/rolldown/tests/rolldown/issues/7009/cjs/index.cjs
@@ -0,0 +1,5 @@
+exports.foo = function a() {
+  return 'foo';
+};
+
+arguments = 1;
diff --git a/crates/rolldown/tests/rolldown/issues/7009/cts/_config.json b/crates/rolldown/tests/rolldown/issues/7009/cts/_config.json
@@ -0,0 +1,12 @@
+{
+  "config": {
+    "input": [
+      {
+        "name": "main",
+        "import": "./index.cts"
+      }
+    ],
+    "format": "cjs"
+  },
+  "expectExecuted": false
+}
diff --git a/crates/rolldown/tests/rolldown/issues/7009/cts/artifacts.snap b/crates/rolldown/tests/rolldown/issues/7009/cts/artifacts.snap
@@ -0,0 +1,17 @@
+---
+source: crates/rolldown_testing/src/integration_test.rs
+---
+# Assets
+
+## main.js
+
+```js
+
+//#region index.cts
+exports.foo = function a() {
+	return "foo";
+};
+arguments = 1;
+
+//#endregion
+```
diff --git a/crates/rolldown/tests/rolldown/issues/7009/cts/index.cts b/crates/rolldown/tests/rolldown/issues/7009/cts/index.cts
@@ -0,0 +1,5 @@
+exports.foo = function a() {
+  return 'foo';
+};
+
+arguments = 1;
diff --git a/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/_config.json b/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/_config.json
@@ -0,0 +1,12 @@
+{
+  "config": {
+    "input": [
+      {
+        "name": "main",
+        "import": "./index.js"
+      }
+    ],
+    "format": "cjs"
+  },
+  "expectExecuted": false
+}
diff --git a/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/artifacts.snap b/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/artifacts.snap
@@ -0,0 +1,17 @@
+---
+source: crates/rolldown_testing/src/integration_test.rs
+---
+# Assets
+
+## main.js
+
+```js
+
+//#region index.js
+exports.foo = function a() {
+	return "foo";
+};
+arguments = 1;
+
+//#endregion
+```
diff --git a/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/index.js b/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/index.js
@@ -0,0 +1,5 @@
+exports.foo = function a() {
+  return 'foo';
+};
+
+arguments = 1;
diff --git a/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/package.json b/crates/rolldown/tests/rolldown/issues/7009/js_type_commonjs/package.json
@@ -0,0 +1,3 @@
+{
+  "type": "commonjs"
+}
diff --git a/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/_config.json b/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/_config.json
@@ -6,7 +6,7 @@
         "name": "index"
       }
     ],
+    "platform": "node",
     "keepNames": true
-  },
-  "expectExecuted": false
+  }
 }
diff --git a/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/artifacts.snap b/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/artifacts.snap
@@ -6,10 +6,11 @@ source: crates/rolldown_testing/src/integration_test.rs
 ## index.js
 
 ```js
-import assert from "node:assert";
+import { createRequire } from "node:module";
 
 // HIDDEN [\0rolldown/runtime.js]
-//#region bar.cjs
+//#region bar.mjs
+var bar_exports = /* @__PURE__ */ __exportAll({ test: () => test$1 });
 var test$1;
 var init_bar = __esmMin((() => {
 	test$1 = /* @__PURE__ */ __name(() => {
@@ -18,7 +19,8 @@ var init_bar = __esmMin((() => {
 }));
 
 //#endregion
-//#region foo.cjs
+//#region foo.mjs
+var foo_exports = /* @__PURE__ */ __exportAll({ default: () => test });
 function test() {
 	return { test: "foo" };
 }
@@ -27,13 +29,15 @@ var init_foo = __esmMin((() => {}));
 //#endregion
 //#region index.cjs
 var require_src = /* @__PURE__ */ __commonJSMin((() => {
-	init_bar();
-	init_foo();
-	assert.strictEqual(test$1.name, "test");
+	const assert = __require("node:assert");
+	const { test: barTest } = (init_bar(), __toCommonJS(bar_exports));
+	const { default: test } = (init_foo(), __toCommonJS(foo_exports));
+	assert.strictEqual(barTest.name, "test");
 	assert.strictEqual(test.name, "test");
 }));
 
 //#endregion
 export default require_src();
 
+export {  };
 ```
diff --git a/.../topics/keep_names/issue_7507/src/bar.cjs → .../topics/keep_names/issue_7507/src/bar.mjs b/.../topics/keep_names/issue_7507/src/bar.cjs → .../topics/keep_names/issue_7507/src/bar.mjs
diff --git a/.../topics/keep_names/issue_7507/src/foo.cjs → .../topics/keep_names/issue_7507/src/foo.mjs b/.../topics/keep_names/issue_7507/src/foo.cjs → .../topics/keep_names/issue_7507/src/foo.mjs
diff --git a/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/index.cjs b/crates/rolldown/tests/rolldown/topics/keep_names/issue_7507/src/index.cjs
@@ -1,6 +1,6 @@
-import assert from 'node:assert';
-import { test as barTest } from './bar.cjs';
-import test from './foo.cjs';
+const assert = require('node:assert');
+const { test: barTest } = require('./bar.mjs');
+const { default: test } = require('./foo.mjs');
 
 assert.strictEqual(barTest.name, 'test');
 assert.strictEqual(test.name, 'test');
diff --git a/crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap b/crates/rolldown/tests/snapshots/integration_rolldown__filename_with_hash.snap
@@ -4660,8 +4660,8 @@ expression: output
 
 # tests/rolldown/issues/4289
 
-- main-!~{000}~.js => main-d6x-NxY7.js
-- lib-!~{001}~.js => lib-jm3gYqNp.js
+- main-!~{000}~.js => main-ckJZUoDu.js
+- lib-!~{001}~.js => lib-BpjDadci.js
 
 # tests/rolldown/issues/4324
 
@@ -4882,6 +4882,18 @@ expression: output
 - _virtual/_rolldown/runtime-!~{001}~.js => _virtual/_rolldown/runtime-Fau4GV7D.js
 - server/index-!~{002}~.js => server/index-Da8_eDWm.js
 
+# tests/rolldown/issues/7009/cjs
+
+- main-!~{000}~.js => main-CgjitbJ5.js
+
+# tests/rolldown/issues/7009/cts
+
+- main-!~{000}~.js => main-B4u3m95-.js
+
+# tests/rolldown/issues/7009/js_type_commonjs
+
+- main-!~{000}~.js => main-CO96sClh.js
+
 # tests/rolldown/issues/7021
 
 - main-!~{000}~.js => main-BuqYlu74.js
@@ -5956,7 +5968,7 @@ expression: output
 
 # tests/rolldown/topics/keep_names/issue_7507/src
 
-- index-!~{000}~.js => index-EsnM9fHZ.js
+- index-!~{000}~.js => index-BPcqbtIz.js
 
 # tests/rolldown/topics/keep_names/issue_7852
 

diff --git a/docs/in-depth/bundling-cjs.md b/docs/in-depth/bundling-cjs.md
@@ -200,6 +200,12 @@ If you find an issue that seems to be caused by this incompatibility, try using
 
 If the heuristic is not working for you, you can use the code in the section above that handles both interpretations. If the import is in a dependency, we recommend to raise an issue to the dependency. In the meantime, you can use [`patch-package`](https://github.com/ds300/patch-package) or [`pnpm patch`](https://pnpm.io/cli/patch) or alternatives as an escape hatch.
 
+### Strict Mode Applied to `.js` files without `"type": "commonjs"` in `package.json`
+
+For files ending with `.js` that do not have `"type": "commonjs"` in the closest `package.json`, Rolldown incorrectly parses the file as ESM ([#7009](https://github.com/rolldown/rolldown/issues/7009)). This means that syntaxes only allowed in non-strict mode (sloppy mode) will be rejected.
+
+For now, you can change the file extension to `.cjs` or add `"type": "commonjs"` to the closest `package.json` as a workaround.
+
 ## Future Plans
 
 Rolldown's first-class support for CommonJS modules enables several potential optimizations: