n-api: add napi_fatal_exception

Author: mafintosh

doc/api/n-api.md

@@ -541,6 +541,19 @@ This API returns true if an exception is pending.
 
 This API can be called even if there is a pending JavaScript exception.
 
+#### napi_fatal_exception
+<!-- YAML
+added: TBA
+-->
+```C
+napi_fatal_exception(napi_env env);
+```
+
+- `[in] env`: The environment that the API is invoked under.
+
+Trigger an `uncaughtException` in JavaScript. Useful if an async
+callback throws an exception with no way to recover.
+
 ### Fatal Errors
 
 In the event of an unrecoverable error in a native module, a fatal error can be

src/node_api.cc

@@ -954,6 +954,16 @@ napi_status napi_get_last_error_info(napi_env env,
   return napi_ok;
 }
 
+void napi_fatal_exception(napi_env env) {
+  if (!env->last_exception.IsEmpty()) {
+    v8::Local<v8::Value> err = v8::Local<v8::Value>::New(
+      env->isolate, env->last_exception);
+    v8::Local<v8::Message> msg = v8::Exception::CreateMessage(
+      env->isolate, err);
+    node::FatalException(env->isolate, err, msg);
+  }
+}
+
 NAPI_NO_RETURN void napi_fatal_error(const char* location,
                                      size_t location_len,
                                      const char* message,
@@ -3353,13 +3363,7 @@ class Work : public node::AsyncResource {
       // If there was an unhandled exception in the complete callback,
       // report it as a fatal exception. (There is no JavaScript on the
       // callstack that can possibly handle it.)
-      if (!env->last_exception.IsEmpty()) {
-        v8::Local<v8::Value> err = v8::Local<v8::Value>::New(
-          env->isolate, env->last_exception);
-        v8::Local<v8::Message> msg = v8::Exception::CreateMessage(
-          env->isolate, err);
-        node::FatalException(env->isolate, err, msg);
-      }
+      napi_fatal_exception(env);
     }
   }
 

src/node_api.h

@@ -112,6 +112,8 @@ NAPI_EXTERN napi_status
 napi_get_last_error_info(napi_env env,
                          const napi_extended_error_info** result);
 
+NAPI_EXTERN void napi_fatal_exception(napi_env env);
+
 NAPI_EXTERN NAPI_NO_RETURN void napi_fatal_error(const char* location,
                                                  size_t location_len,
                                                  const char* message,