Add a Runtime::snapshot method for nodeMap state serialization

runtime/elem/GraphNode.h

@@ -59,6 +59,9 @@ namespace elem
         template <typename ValueType>
         ValueType getPropertyWithDefault(std::string const& key, ValueType const& df);
 
+        // Returns a copy of the entire property object in its current state
+        js::Object getProperties();
+
         // Process the next block of audio data.
         //
         // Users must override this method when creating a custom GraphNode.
@@ -122,4 +125,9 @@ namespace elem
         return df;
     }
 
+    template <typename FloatType>
+    js::Object GraphNode<FloatType>::getProperties() {
+        return js::Object(props.begin(), props.end());
+    }
+
 } // namespace elem

runtime/elem/Runtime.h

@@ -87,6 +87,7 @@ namespace elem
         // Intentionally, this does not provide access to the values in the map.
         typename SharedResourceMap<FloatType>::KeyViewType getSharedResourceMapKeys();
 
+        //==============================================================================
         // For registering custom GraphNode factory functions.
         //
         // New node types must inherit GraphNode, and the factory function must produce a shared
@@ -98,6 +99,10 @@ namespace elem
         using NodeFactoryFn = std::function<std::shared_ptr<GraphNode<FloatType>>(NodeId const id, double sampleRate, int const blockSize)>;
         int registerNodeType (std::string const& type, NodeFactoryFn && fn);
 
+        //==============================================================================
+        // Returns a copy of the internal graph state representing all known nodes and properties
+        js::Object snapshot();
+
     private:
         //==============================================================================
         // The rendering interface
@@ -419,6 +424,18 @@ namespace elem
         return ReturnCode::Ok();
     }
 
+    template <typename FloatType>
+    js::Object Runtime<FloatType>::snapshot()
+    {
+        js::Object ret;
+
+        for (auto& [nodeId, node] : nodeTable) {
+            ret.insert({nodeIdToHex(nodeId), node->getProperties()});
+        }
+
+        return ret;
+    }
+
     //==============================================================================
     template <typename FloatType>
     void Runtime<FloatType>::traverse(std::set<NodeId>& visited, std::vector<NodeId>& visitOrder, NodeId const& n) {