feat: add Catch method to Promise class

Author: miguelmarcondesf

napi-inl.h

@@ -2857,6 +2857,28 @@ inline MaybeOrValue<Promise> Promise::Then(napi_value onFulfilled, napi_value on
 #endif
 }
 
+inline MaybeOrValue<Promise> Promise::Catch(napi_value onRejected) const {
+  EscapableHandleScope scope(_env);
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  MaybeOrValue<Value> catchMethodMaybe = Get("catch");
+  Function catchMethod = catchMethodMaybe.Unwrap().As<Function>();
+#else
+  Function catchMethod = Get("catch").As<Function>();
+#endif
+  MaybeOrValue<Value> result = catchMethod.Call(*this, {onRejected});
+#ifdef NODE_ADDON_API_ENABLE_MAYBE
+  if (result.IsJust()) {
+    return Just(scope.Escape(result.Unwrap()).As<Promise>());
+  }
+  return Nothing<Promise>();
+#else
+  if (scope.Env().IsExceptionPending()) {
+    return Promise();
+  }
+  return scope.Escape(result).As<Promise>();
+#endif
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Buffer<T> class
 ////////////////////////////////////////////////////////////////////////////////

napi.h

@@ -1579,6 +1579,7 @@ class Promise : public Object {
 
   MaybeOrValue<Promise> Then(napi_value onFulfilled) const;
   MaybeOrValue<Promise> Then(napi_value onFulfilled, napi_value onRejected) const;
+  MaybeOrValue<Promise> Catch(napi_value onRejected) const;
 };
 
 template <typename T>

test/promise.cc

@@ -74,6 +74,22 @@ Value ThenMethodOnFulfilledOnRejectedReject(const CallbackInfo& info) {
   return result;
 }
 
+Value CatchMethod(const CallbackInfo& info) {
+  auto deferred = Promise::Deferred::New(info.Env());
+  Function onRejected = info[0].As<Function>();
+
+  Promise resultPromise = MaybeUnwrap(deferred.Promise().Catch(onRejected));
+
+  bool isPromise = resultPromise.IsPromise();
+  deferred.Reject(String::New(info.Env(), "Rejected"));
+
+  Object result = Object::New(info.Env());
+  result["isPromise"] = Boolean::New(info.Env(), isPromise);
+  result["promise"] = resultPromise;
+
+  return result;
+}
+
 Object InitPromise(Env env) {
   Object exports = Object::New(env);
 
@@ -87,6 +103,7 @@ Object InitPromise(Env env) {
       Function::New(env, ThenMethodOnFulfilledOnRejectedResolve);
   exports["thenMethodOnFulfilledOnRejectedReject"] =
       Function::New(env, ThenMethodOnFulfilledOnRejectedReject);
+  exports["catchMethod"] = Function::New(env, CatchMethod);
 
   return exports;
 }