Remove this tracking for files with module syntax

parcel-bundler · Oct 20, 2023 · 7103543 · 7103543
1 parent 993fc0a
commit 7103543
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Showing 2 changed files with 20 additions and 25 deletions.
diff --git a/packages/transformers/js/core/src/collect.rs b/packages/transformers/js/core/src/collect.rs
@@ -692,6 +692,11 @@ impl Visit for Collect {
         return;
       }
       Expr::This(_this) => {
+        if self.is_module {
+          // Don't track this bindings if ESM syntax is present
+          return;
+        }
+
         if self.in_module_this {
           handle_export!();
         } else if !self.in_class {
@@ -770,27 +775,6 @@ impl Visit for Collect {
           self.used_imports.insert(id!(ident));
         }
       }
-      Expr::Bin(bin_expr) => {
-        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 () {}
-          if matches!(bin_expr.op, BinaryOp::LogicalAnd) && matches!(*bin_expr.left, Expr::This(..))
-          {
-            match &*bin_expr.right {
-              Expr::Member(member_expr) => {
-                if matches!(*member_expr.obj, Expr::This(..))
-                  && matches!(member_expr.prop, MemberProp::Ident(..))
-                {
-                  return;
-                }
-              }
-              _ => {}
-            }
-          }
-        }
-        node.visit_children_with(self);
-      }
       _ => {
         node.visit_children_with(self);
       }
@@ -823,7 +807,7 @@ impl Visit for Collect {
   }
 
   fn visit_this_expr(&mut self, node: &ThisExpr) {
-    if self.in_module_this {
+    if !self.is_module && self.in_module_this {
       self.has_cjs_exports = true;
       self.static_cjs_exports = false;
       self.add_bailout(node.span, BailoutReason::FreeExports);

diff --git a/packages/transformers/js/core/src/hoist.rs b/packages/transformers/js/core/src/hoist.rs
@@ -1140,11 +1140,21 @@ mod tests {
     );
 
     let mut parser = Parser::new_from(lexer);
-    match parser.parse_module() {
-      Ok(module) => swc_core::common::GLOBALS.set(&Globals::new(), || {
+    match parser.parse_program() {
+      Ok(program) => swc_core::common::GLOBALS.set(&Globals::new(), || {
         swc_core::ecma::transforms::base::helpers::HELPERS.set(
           &swc_core::ecma::transforms::base::helpers::Helpers::new(false),
           || {
+            let is_module = program.is_module();
+            let module = match program {
+              Program::Module(module) => module,
+              Program::Script(script) => Module {
+                span: script.span,
+                shebang: None,
+                body: script.body.into_iter().map(ModuleItem::Stmt).collect(),
+              },
+            };
+
             let unresolved_mark = Mark::fresh(Mark::root());
             let global_mark = Mark::fresh(Mark::root());
             let module = module.fold_with(&mut resolver(unresolved_mark, global_mark, false));
@@ -1155,7 +1165,7 @@ mod tests {
               Mark::fresh(Mark::root()),
               global_mark,
               true,
-              true,
+              is_module,
             );
             module.visit_with(&mut collect);
 
@@ -1445,6 +1455,7 @@ mod tests {
     // We want to avoid marking these modules as CJS
     let (collect, _code, _hoist) = parse(
       r#"
+      import 'something';
       var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || function () {}
     "#,
     );