util: use V8 C++ API for inspecting Promises

PR-URL: https://github.com/nodejs/node/pull/12254
Refs: https://github.com/nodejs/node/issues/11875
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Josh Gavant <josh.gavant@outlook.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/src/node_util.cc b/src/node_util.cc
index 813995de79..fe01717131 100644
--- a/src/node_util.cc
+++ b/src/node_util.cc
@@ -14,6 +14,7 @@ using v8::Integer;
 using v8::Local;
 using v8::Object;
 using v8::Private;
+using v8::Promise;
 using v8::Proxy;
 using v8::Value;
 
@@ -43,6 +44,24 @@ using v8::Value;
   VALUE_METHOD_MAP(V)
 #undef V
 
+static void GetPromiseDetails(const FunctionCallbackInfo<Value>& args) {
+  // Return undefined if it's not a Promise.
+  if (!args[0]->IsPromise())
+    return;
+
+  auto isolate = args.GetIsolate();
+
+  Local<Promise> promise = args[0].As<Promise>();
+  Local<Array> ret = Array::New(isolate, 2);
+
+  int state = promise->State();
+  ret->Set(0, Integer::New(isolate, state));
+  if (state != Promise::PromiseState::kPending)
+    ret->Set(1, promise->Result());
+
+  args.GetReturnValue().Set(ret);
+}
+
 static void GetProxyDetails(const FunctionCallbackInfo<Value>& args) {
   // Return undefined if it's not a proxy.
   if (!args[0]->IsProxy())
@@ -148,8 +167,19 @@ void Initialize(Local<Object> target,
     Integer::NewFromUnsigned(env->isolate(), NODE_PUSH_VAL_TO_ARRAY_MAX),
     v8::ReadOnly).FromJust();
 
+#define V(name)                                                               \
+  target->Set(context,                                                        \
+              FIXED_ONE_BYTE_STRING(env->isolate(), #name),                   \
+              Integer::New(env->isolate(), Promise::PromiseState::name))      \
+    .FromJust()
+  V(kPending);
+  V(kFulfilled);
+  V(kRejected);
+#undef V
+
   env->SetMethod(target, "getHiddenValue", GetHiddenValue);
   env->SetMethod(target, "setHiddenValue", SetHiddenValue);
+  env->SetMethod(target, "getPromiseDetails", GetPromiseDetails);
   env->SetMethod(target, "getProxyDetails", GetProxyDetails);
 
   env->SetMethod(target, "startSigintWatchdog", StartSigintWatchdog);