Method IsPlainObject

src/util/binder.cpp:51–58

An object is "plain" if its prototype is null or a top-level prototype (i.e., some realm's Object.prototype). Rather than comparing against the current realm's Object.prototype -- which would reject plain objects from other contexts, such as the "vm" module -- we walk to the top of the prototype chain. A plain object's chain is exactly "obj -> proto -> null", so its immediate prototype must itself

	// so its immediate prototype must itself have a null prototype. This mirrors
	// the cross-realm heuristic used by lodash's isPlainObject.
	static bool IsPlainObject(Napi::Env env, Napi::Object obj) {
		Napi::Value proto = GetPrototype(env, obj);
		if (proto.IsEmpty()) return false;
		if (proto.IsNull()) return true;
		Napi::Value grandproto = GetPrototype(env, proto.As<Napi::Object>());
		if (grandproto.IsEmpty()) return false;
		return grandproto.IsNull();
	}

	void Fail(Napi::Value (*Throw)(Napi::Env, const char*), Napi::Env env, const char* message) {
		assert(success == true);