Remove this exports tracking for files with module syntax

packages/core/integration-tests/test/scope-hoisting.js

@@ -17,6 +17,7 @@ import {
   overlayFS,
   run,
   runBundle,
+  fsFixture,
 } from '@parcel/test-utils';
 
 const bundle = (name, opts = {}) => {
@@ -2487,6 +2488,23 @@ describe('scope hoisting', function () {
       assert.equal(await output, 42);
     });
 
+    it('should handle TSC polyfills', async () => {
+      await fsFixture(overlayFS, __dirname)`
+        tsc-polyfill-es6
+          library.js:
+            var __polyfill = (this && this.__polyfill) || function (a) {return a;};
+            export default __polyfill('es6')
+
+          index.js:
+            import value from './library';
+            output = value;`;
+
+      let b = await bundle(path.join(__dirname, 'tsc-polyfill-es6/index.js'), {
+        inputFS: overlayFS,
+      });
+      assert.equal(await run(b), 'es6');
+    });
+
     describe("considers an asset's closest package.json for sideEffects, not the package through which it found the asset", () => {
       it('handles redirects up the tree', async () => {
         let b = await bundle(
@@ -5265,6 +5283,29 @@ describe('scope hoisting', function () {
 
       assert.deepEqual(await run(b), {test: 2});
     });
+
+    it('should handle TSC polyfills', async () => {
+      await fsFixture(overlayFS, __dirname)`
+        tsc-polyfill-commonjs
+          library.js:
+            "use strict";
+            var __polyfill = (this && this.__polyfill) || function (a) {return a;};
+            exports.value = __polyfill('cjs')
+
+          index.js:
+            const value = require('./library');
+            output = value;
+      `;
+
+      let b = await bundle(
+        path.join(__dirname, 'tsc-polyfill-commonjs/index.js'),
+        {
+          inputFS: overlayFS,
+        },
+      );
+
+      assert.deepEqual(await run(b), {value: 'cjs'});
+    });
   });
 
   it('should not throw with JS included from HTML', async function () {

packages/transformers/js/core/src/collect.rs

@@ -78,6 +78,7 @@ pub struct Collect {
   in_function: bool,
   in_assign: bool,
   in_class: bool,
+  is_module: bool,
 }
 
 #[derive(Debug, Serialize)]
@@ -120,12 +121,14 @@ impl Collect {
     ignore_mark: Mark,
     global_mark: Mark,
     trace_bailouts: bool,
+    is_module: bool,
   ) -> Self {
     Collect {
       source_map,
       decls,
       ignore_mark,
       global_mark,
+      is_module,
       static_cjs_exports: true,
       has_cjs_exports: false,
       is_esm: false,
@@ -768,7 +771,7 @@ impl Visit for Collect {
         }
       }
       Expr::Bin(bin_expr) => {
-        if self.in_module_this {
+        if self.is_module & self.in_module_this {
           // Some TSC polyfills use a pattern like below.
           // We want to avoid marking these modules as CJS
           // e.g. var _polyfill = (this && this.polyfill) || function () {}

packages/transformers/js/core/src/fs.rs

@@ -17,6 +17,7 @@ pub fn inline_fs<'a>(
   global_mark: Mark,
   project_root: &'a str,
   deps: &'a mut Vec<DependencyDescriptor>,
+  is_module: bool,
 ) -> impl Fold + 'a {
   InlineFS {
     filename: Path::new(filename).to_path_buf(),
@@ -26,6 +27,7 @@ pub fn inline_fs<'a>(
       Mark::fresh(Mark::root()),
       global_mark,
       false,
+      is_module,
     ),
     global_mark,
     project_root,

packages/transformers/js/core/src/hoist.rs

@@ -1155,6 +1155,7 @@ mod tests {
               Mark::fresh(Mark::root()),
               global_mark,
               true,
+              true,
             );
             module.visit_with(&mut collect);
 

packages/transformers/js/core/src/lib.rs

@@ -252,6 +252,7 @@ pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
                 ),
               ));
 
+              let is_module = module.is_module();
               // If it's a script, convert into module. This needs to happen after
               // the resolver (which behaves differently for non-/strict mode).
               let module = match module {
@@ -342,6 +343,7 @@ pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
                       global_mark,
                       &config.project_root,
                       &mut fs_deps,
+                      is_module
                     ),
                     should_inline_fs
                   ),
@@ -448,6 +450,7 @@ pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
                 ignore_mark,
                 global_mark,
                 config.trace_bailouts,
+                is_module,
               );
               module.visit_with(&mut collect);
               if let Some(bailouts) = &collect.bailouts {