worker: add hasRef() to the handle object

This should help projects like
https://github.com/mafintosh/why-is-node-running and
https://github.com/facebook/jest to detect if Worker instances are
keeping the event loop active correctly.

Fixes: https://github.com/nodejs/node/issues/42091
Refs: https://github.com/mafintosh/why-is-node-running/issues/59
Signed-off-by: Darshan Sen <raisinten@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/42756
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/node_worker.cc b/src/node_worker.cc
index 04cd60b2453..2a509165c25 100644
--- a/src/node_worker.cc
+++ b/src/node_worker.cc
@@ -680,6 +680,12 @@ void Worker::Ref(const FunctionCallbackInfo<Value>& args) {
   }
 }
 
+void Worker::HasRef(const FunctionCallbackInfo<Value>& args) {
+  Worker* w;
+  ASSIGN_OR_RETURN_UNWRAP(&w, args.This());
+  args.GetReturnValue().Set(w->has_ref_);
+}
+
 void Worker::Unref(const FunctionCallbackInfo<Value>& args) {
   Worker* w;
   ASSIGN_OR_RETURN_UNWRAP(&w, args.This());
@@ -842,6 +848,7 @@ void InitWorker(Local<Object> target,
 
     env->SetProtoMethod(w, "startThread", Worker::StartThread);
     env->SetProtoMethod(w, "stopThread", Worker::StopThread);
+    env->SetProtoMethod(w, "hasRef", Worker::HasRef);
     env->SetProtoMethod(w, "ref", Worker::Ref);
     env->SetProtoMethod(w, "unref", Worker::Unref);
     env->SetProtoMethod(w, "getResourceLimits", Worker::GetResourceLimits);
@@ -905,6 +912,7 @@ void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
   registry->Register(Worker::New);
   registry->Register(Worker::StartThread);
   registry->Register(Worker::StopThread);
+  registry->Register(Worker::HasRef);
   registry->Register(Worker::Ref);
   registry->Register(Worker::Unref);
   registry->Register(Worker::GetResourceLimits);