feat(linter): handle cjs `module.exports = {} as default export (#2493)

crates/oxc_ast/src/ast/js.rs

@@ -665,11 +665,7 @@ impl<'a> MemberExpression<'a> {
         }
     }
 
-    pub fn through_optional_is_specific_member_access(
-        &'a self,
-        object: &str,
-        property: &str,
-    ) -> bool {
+    pub fn through_optional_is_specific_member_access(&self, object: &str, property: &str) -> bool {
         let object_matches = match self.object().without_parenthesized() {
             Expression::ChainExpression(x) => match &x.expression {
                 ChainElement::CallExpression(_) => false,
@@ -686,7 +682,7 @@ impl<'a> MemberExpression<'a> {
     }
 
     /// Whether it is a static member access `object.property`
-    pub fn is_specific_member_access(&'a self, object: &str, property: &str) -> bool {
+    pub fn is_specific_member_access(&self, object: &str, property: &str) -> bool {
         self.object().is_specific_id(object)
             && self.static_property_name().is_some_and(|p| p == property)
     }

crates/oxc_linter/src/rules/import/default.rs

@@ -39,7 +39,9 @@ impl Rule for Default {
     fn run_once(&self, ctx: &LintContext<'_>) {
         let module_record = ctx.semantic().module_record();
         for import_entry in &module_record.import_entries {
-            let ImportImportName::Default(_) = import_entry.import_name else { continue };
+            let ImportImportName::Default(default_span) = import_entry.import_name else {
+                continue;
+            };
 
             let specifier = import_entry.module_request.name();
             let Some(remote_module_record_ref) = module_record.loaded_modules.get(specifier) else {
@@ -49,10 +51,7 @@ impl Rule for Default {
             if remote_module_record_ref.export_default.is_none()
                 && !remote_module_record_ref.exported_bindings.contains_key("default")
             {
-                ctx.diagnostic(DefaultDiagnostic(
-                    specifier.to_string(),
-                    import_entry.module_request.span(),
-                ));
+                ctx.diagnostic(DefaultDiagnostic(specifier.to_string(), default_span));
             }
         }
     }
@@ -72,9 +71,7 @@ fn test() {
         r#"import CoolClass from "./default-class""#,
         r#"import bar, { baz } from "./default-export""#,
         r#"import crypto from "crypto""#,
-        // TODO: module.exports
-        // r#"import common from "./common""#,
-
+        r#"import common from "./common""#,
         // No longer valid syntax
         // r#"export bar from "./bar""#,
         // r#"export bar, { foo } from "./bar""#,

crates/oxc_linter/src/snapshots/default.snap

@@ -3,9 +3,9 @@ source: crates/oxc_linter/src/tester.rs
 expression: default
 ---
   ⚠ eslint-plugin-import(default): No default export found in imported module "./named-exports"
-   ╭─[index.js:1:17]
+   ╭─[index.js:1:8]
  1 │ import baz from "./named-exports"
-   ·                 ─────────────────
+   ·        ───
    ╰────
   help: does "./named-exports" have the default export?
 
@@ -28,15 +28,15 @@ expression: default
    ╰────
 
   ⚠ eslint-plugin-import(default): No default export found in imported module "./re-export"
-   ╭─[index.js:1:24]
+   ╭─[index.js:1:8]
  1 │ import barDefault from "./re-export"
-   ·                        ─────────────
+   ·        ──────────
    ╰────
   help: does "./re-export" have the default export?
 
   ⚠ eslint-plugin-import(default): No default export found in imported module "./typescript"
-   ╭─[index.js:1:20]
+   ╭─[index.js:1:8]
  1 │ import foobar from "./typescript"
-   ·                    ──────────────
+   ·        ──────
    ╰────
   help: does "./typescript" have the default export?

crates/oxc_semantic/src/module_record/builder.rs

@@ -367,21 +367,34 @@ impl ModuleRecordBuilder {
         }
     }
 
-    // Add export binding `foo` of `
-    // * exports.foo = bar`
-    // * module.exports.foo = bar`
+    // Add export binding for
+    // * exports.foo = bar
+    // * module.exports.foo = bar
+    // * module.exports = foo
     fn handle_cjs_export(&mut self, expr: &Expression) {
         let Expression::AssignmentExpression(assign_expr) = expr else { return };
         let AssignmentTarget::SimpleAssignmentTarget(target) = &assign_expr.left else { return };
         let SimpleAssignmentTarget::MemberAssignmentTarget(member_expr) = target else { return };
         match member_expr.object() {
-            Expression::Identifier(ident) if ident.name == "exports" => {}
-            Expression::MemberExpression(member_expr)
-                if matches!(member_expr.object(), Expression::Identifier(ident) if ident.name == "module")
-                    && member_expr.static_property_name() == Some("exports") => {}
-            _ => return,
+            // exports.foo = bar
+            Expression::Identifier(ident) if ident.name == "exports" => {
+                let Some((span, name)) = member_expr.static_property_info() else { return };
+                self.add_export_binding(name.into(), span);
+            }
+            // module.exports = {}
+            Expression::Identifier(_)
+                if member_expr.is_specific_member_access("module", "exports") =>
+            {
+                self.add_default_export(assign_expr.right.span());
+            }
+            // module.exports.foo = bar
+            Expression::MemberExpression(inner_member_expr)
+                if inner_member_expr.is_specific_member_access("module", "exports") =>
+            {
+                let Some((span, name)) = member_expr.static_property_info() else { return };
+                self.add_export_binding(name.into(), span);
+            }
+            _ => {}
         }
-        let Some((span, name)) = member_expr.static_property_info() else { return };
-        self.add_export_binding(name.into(), span);
     }
 }