src: improve module loader readability

Various improvements on readability, performance and
conformity to the Node core coding style in the ESM loader C++ code:

- `isolate` for the `Isolate*`, `context` for the `Local<Context>`
- Less reliance on `auto` where it’s unnecessary/increases cognitive
  overhead
- Shorter paths to failure via `.ToLocal()` & co
- Do not keep pending exceptions around e.g. for failed `JSON` parsing
- Use `Maybe` types to get explicit error status forwarding
- Remove an unnecessary handle scope
- Add `nullptr` checks for unwrapped host objects
- Remove unused code
- Use `CamelCase` for function names
- Use `const Foo&` instead of copying values whenever possible
- Pass along the `Environment*` explicitly

PR-URL: https://github.com/nodejs/node/pull/16536
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/node_url.h b/src/node_url.h
index 872f2fbc97..6b526d15b0 100644
--- a/src/node_url.h
+++ b/src/node_url.h
@@ -118,6 +118,9 @@ class URL {
   URL(std::string input, const URL* base) :
       URL(input.c_str(), input.length(), base) {}
 
+  URL(std::string input, const URL& base) :
+      URL(input.c_str(), input.length(), &base) {}
+
   URL(std::string input, std::string base) :
       URL(input.c_str(), input.length(), base.c_str(), base.length()) {}
 
@@ -168,6 +171,13 @@ class URL {
 
   const Local<Value> ToObject(Environment* env) const;
 
+  URL(const URL&) = default;
+  URL& operator=(const URL&) = default;
+  URL(URL&&) = default;
+  URL& operator=(URL&&) = default;
+
+  URL() : URL("") {}
+
  private:
   struct url_data context_;
 };