fix(compartment-mapper): change how parse-cjs.js treats exports to al…

…ign with behavior of cjs in Node.js; make execute synchronous

packages/compartment-mapper/src/parse-cjs.js

@@ -25,35 +25,42 @@ export const parseCjs = async (
    * @param {Compartment} compartment
    * @param {Record<string, string>} resolvedImports
    */
-  const execute = async (moduleExports, compartment, resolvedImports) => {
+  const execute = (moduleExports, compartment, resolvedImports) => {
     const functor = compartment.evaluate(
       `(function (require, exports, module, __filename, __dirname) { ${source} //*/\n})\n//# sourceURL=${location}`,
     );
-
+    let exportsReferenceCopy = moduleExports;
     const module = freeze({
       get exports() {
-        return moduleExports;
+        return exportsReferenceCopy;
       },
       set exports(value) {
-        moduleExports.default = value;
+        exportsReferenceCopy = value;
       },
     });
 
     const require = freeze((/** @type {string} */ importSpecifier) => {
       const namespace = compartment.importNow(resolvedImports[importSpecifier]);
       if (namespace.default !== undefined) {
-        return namespace.default;
+        if (Object.keys(namespace).length > 1) {
+          return { ...namespace.default, ...namespace }; // this resembles Node's behavior more closely
+        } else {
+          return namespace.default;
+        }
       }
       return namespace;
     });
 
     functor(
       require,
-      moduleExports,
+      exportsReferenceCopy,
       module,
       location, // __filename
       new URL('./', location).toString(), // __dirname
     );
+    if (exportsReferenceCopy !== moduleExports) {
+      moduleExports.default = exportsReferenceCopy;
+    }
   };
 
   return {