[node] capture invalid input data as `ParseError` objects

This allows us to distinguish them from other types of errors

3 files changed, 43 insertions, 5 deletions

diff --git a/platform/node/src/node_map.cpp b/platform/node/src/node_map.cpp
index 0cc93d7e95..7dbccfcf41 100644
--- a/platform/node/src/node_map.cpp
+++ b/platform/node/src/node_map.cpp
@@ -47,6 +47,7 @@ struct NodeMap::RenderOptions {
 };
 
 Nan::Persistent<v8::Function> NodeMap::constructor;
+Nan::Persistent<v8::Object> NodeMap::parseError;
 
 static const char* releasedMessage() {
     return "Map resources have already been released";
@@ -57,6 +58,20 @@ void NodeMapObserver::onDidFailLoadingMap(std::exception_ptr error) {
 }
 
 void NodeMap::Init(v8::Local<v8::Object> target) {
+    // Define a custom error class for parse errors
+    auto script = Nan::New<v8::UnboundScript>(Nan::New(R"JS(
+class ParseError extends Error {
+  constructor(...params) {
+    super(...params);
+    if (Error.captureStackTrace) {
+      Error.captureStackTrace(this, ParseError);
+    }
+  }
+}
+ParseError)JS").ToLocalChecked()).ToLocalChecked();
+    parseError.Reset(Nan::To<v8::Object>(Nan::RunScript(script).ToLocalChecked()).ToLocalChecked());
+    Nan::Set(target, Nan::New("ParseError").ToLocalChecked(), Nan::New(parseError));
+
     v8::Local<v8::FunctionTemplate> tpl = Nan::New<v8::FunctionTemplate>(New);
 
     tpl->SetClassName(Nan::New("Map").ToLocalChecked());
@@ -216,6 +231,8 @@ void NodeMap::Load(const Nan::FunctionCallbackInfo<v8::Value>& info) {
 
     try {
         nodeMap->map->getStyle().loadJSON(style);
+    } catch (const mbgl::util::StyleParseException& ex) {
+        return Nan::ThrowError(ParseError(ex.what()));
     } catch (const std::exception &ex) {
         return Nan::ThrowError(ex.what());
     }
@@ -408,9 +425,11 @@ void NodeMap::Render(const Nan::FunctionCallbackInfo<v8::Value>& info) {
         nodeMap->req = std::make_unique<RenderRequest>(Nan::To<v8::Function>(info[1]).ToLocalChecked());
 
         nodeMap->startRender(std::move(options));
-    } catch (mbgl::style::conversion::Error& err) {
+    } catch (const mbgl::style::conversion::Error& err) {
         return Nan::ThrowTypeError(err.message.c_str());
-    } catch (mbgl::util::Exception &ex) {
+    } catch (const mbgl::util::StyleParseException& ex) {
+        return Nan::ThrowError(ParseError(ex.what()));
+    } catch (const mbgl::util::Exception &ex) {
         return Nan::ThrowError(ex.what());
     }
 
@@ -459,6 +478,11 @@ void NodeMap::startRender(NodeMap::RenderOptions options) {
     uv_ref(reinterpret_cast<uv_handle_t *>(async));
 }
 
+v8::Local<v8::Value> NodeMap::ParseError(const char* msg) {
+    v8::Local<v8::Value> argv[] = { Nan::New(msg).ToLocalChecked() };
+    return Nan::CallAsConstructor(Nan::New(parseError), 1, argv).ToLocalChecked();
+}
+
 void NodeMap::renderFinished() {
     assert(req);
 
@@ -480,16 +504,19 @@ void NodeMap::renderFinished() {
     v8::Local<v8::Object> target = Nan::New<v8::Object>();
 
     if (error) {
-        std::string errorMessage;
+        v8::Local<v8::Value> err;
 
         try {
             std::rethrow_exception(error);
+            assert(false);
+        } catch (const mbgl::util::StyleParseException& ex) {
+            err = ParseError(ex.what());
         } catch (const std::exception& ex) {
-            errorMessage = ex.what();
+            err = Nan::Error(ex.what());
         }
 
         v8::Local<v8::Value> argv[] = {
-            Nan::Error(errorMessage.c_str())
+            err
         };
 
         // This must be empty to be prepared for the next render call.
diff --git a/platform/node/src/node_map.hpp b/platform/node/src/node_map.hpp
index 19df095481..52fc1ef659 100644
--- a/platform/node/src/node_map.hpp
+++ b/platform/node/src/node_map.hpp
@@ -37,6 +37,7 @@ public:
     ~NodeMap();
 
     static Nan::Persistent<v8::Function> constructor;
+    static Nan::Persistent<v8::Object> parseError;
 
     static void Init(v8::Local<v8::Object>);
 
@@ -67,6 +68,8 @@ public:
     static void DumpDebugLogs(const Nan::FunctionCallbackInfo<v8::Value>&);
     static void QueryRenderedFeatures(const Nan::FunctionCallbackInfo<v8::Value>&);
 
+    static v8::Local<v8::Value> ParseError(const char* msg);
+
     void startRender(RenderOptions options);
     void renderFinished();
 
diff --git a/platform/node/test/js/map.test.js b/platform/node/test/js/map.test.js
index 2223e54aaa..4a71d72046 100644
--- a/platform/node/test/js/map.test.js
+++ b/platform/node/test/js/map.test.js
@@ -323,6 +323,10 @@ test('Map', function(t) {
                 map.load('""');
             }, /Failed to parse style: style must be an object/);
 
+            t.throws(function() {
+                map.load('""');
+            }, mbgl.ParseError);
+
             map.release();
             t.end();
         });
@@ -341,6 +345,10 @@ test('Map', function(t) {
 
             t.throws(function() {
                 map.load('invalid');
+            }, mbgl.ParseError);
+
+            t.throws(function() {
+                map.load('invalid');
             }, /Failed to parse style: 0 - Invalid value./);
         });