src: clean up PackageConfig pseudo-boolean fields

PR-URL: #21987
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

src/env.h

@@ -65,23 +65,15 @@ class Worker;
 namespace loader {
 class ModuleWrap;
 
-struct Exists {
-  enum Bool { Yes, No };
-};
-
-struct IsValid {
-  enum Bool { Yes, No };
-};
-
-struct HasMain {
-  enum Bool { Yes, No };
-};
-
 struct PackageConfig {
-  const Exists::Bool exists;
-  const IsValid::Bool is_valid;
-  const HasMain::Bool has_main;
-  const std::string main;
+  enum class Exists { Yes, No };
+  enum class IsValid { Yes, No };
+  enum class HasMain { Yes, No };
+
+  Exists exists;
+  IsValid is_valid;
+  HasMain has_main;
+  std::string main;
 };
 }  // namespace loader
 
@@ -673,7 +665,8 @@ class Environment {
 
   std::unordered_multimap<int, loader::ModuleWrap*> module_map;
 
-  std::unordered_map<std::string, loader::PackageConfig> package_json_cache;
+  std::unordered_map<std::string, const loader::PackageConfig>
+      package_json_cache;
 
   inline double* heap_statistics_buffer() const;
   inline void set_heap_statistics_buffer(double* pointer);

src/module_wrap.cc

@@ -488,8 +488,12 @@ Maybe<uv_file> CheckFile(const std::string& path,
   return Just(fd);
 }
 
+using Exists = PackageConfig::Exists;
+using IsValid = PackageConfig::IsValid;
+using HasMain = PackageConfig::HasMain;
+
 const PackageConfig& GetPackageConfig(Environment* env,
-                                                   const std::string path) {
+                                      const std::string& path) {
   auto existing = env->package_json_cache.find(path);
   if (existing != env->package_json_cache.end()) {
     return existing->second;
@@ -530,7 +534,7 @@ const PackageConfig& GetPackageConfig(Environment* env,
   }
 
   Local<Value> pkg_main;
-  HasMain::Bool has_main = HasMain::No;
+  HasMain has_main = HasMain::No;
   std::string main_std;
   if (pkg_json->Get(env->context(), env->main_string()).ToLocal(&pkg_main)) {
     has_main = HasMain::Yes;