Node bridge memory cleanup

bridge/node/README.md

@@ -92,7 +92,7 @@ const includePending: boolean = true;
 
 const connections: DsnpGraphEdge[] = graph.getConnectionsForUserGraph(dsnpUserId, schemaId, includePending);
 
-// Free the graph state
+// It is important to free the graph state from memory
 graph.freeGraphState();
 
 ```
@@ -178,6 +178,7 @@ The SDK provides various type definitions that can be used with the Graph class
 
   const updates = graph.exportUpdates();
 
+  // It is important to free the graph state from memory
   graph.freeGraphState();
 
   ```
@@ -204,6 +205,7 @@ The SDK provides various type definitions that can be used with the Graph class
 
   const updates = graph.exportUpdates();
 
+  // It is important to free the graph state from memory
   graph.freeGraphState();
 
   ```
@@ -236,6 +238,7 @@ The SDK provides various type definitions that can be used with the Graph class
 
   const deserialized_keys = Graph.deserializeDsnpKeys(dsnp_keys);
 
+  // It is important to free the graph state from memory
   graph.freeGraphState();
 
   ```
@@ -275,6 +278,7 @@ The SDK provides various type definitions that can be used with the Graph class
 
   const exported_updates = graph.exportUpdates();
 
+  // It is important to free the graph state from memory
   graph.freeGraphState();
 
   ```
@@ -340,4 +344,13 @@ The SDK provides various type definitions that can be used with the Graph class
 
   const applied = graph.applyActions(actions);
 
+  // It is important to free the graph state from memory
+  graph.freeGraphState();
+
   ```
+### Memory management
+Creating any `Graph` instance allocates some memory which should be released manually by calling `graph.freeGraphState()` at the end of
+graph operations.
+
+Even though we have implemented `FinalizationRegistry`, based on the [documentations](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/FinalizationRegistry#avoid_where_possible) it is not a reliable
+way of releasing memory and the best practice is still manual release.

bridge/node/js/graph.ts

@@ -15,11 +15,28 @@ import {
 import { EnvironmentInterface } from "./models/environment";
 
 export class Graph {
+  /// while there is no guarantee that this will free the allocated resources, and we should always manually
+  /// call freeGraphState for cleanup, having FinalizationRegistry might help in some cases that we forgot.
+  static #finalizerInstance: FinalizationRegistry<number>;
+
   /// The handle to the native graph state
-  private handle: number;
+  private readonly handle: number;
 
   constructor(environment: EnvironmentInterface) {
-    this.handle = graphsdkModule.initializeGraphState(environment);
+    if (!Graph.#finalizerInstance) {
+      Graph.#finalizerInstance = new FinalizationRegistry<number>(
+        (handle: number) => {
+          try {
+            graphsdkModule.freeGraphState(handle);
+          } catch {
+            // nothing to do here
+          }
+        },
+      );
+    }
+    const my_handle = graphsdkModule.initializeGraphState(environment);
+    Graph.#finalizerInstance.register(this, my_handle);
+    this.handle = my_handle;
   }
 
   getGraphHandle(): number {

bridge/node/node-example-client/index.ts

@@ -1,10 +1,10 @@
 import { Graph, EnvironmentInterface, Action, DsnpKeys, EnvironmentType, ConnectAction, Connection, ConnectionType, PrivacyType } from "@dsnp/graph-sdk";
 
-const environment: EnvironmentInterface =  {environmentType: EnvironmentType.Mainnet};
-const graph = new Graph(environment);
+function interactWithGraph() {
+    const environment: EnvironmentInterface =  {environmentType: EnvironmentType.Mainnet};
+    const graph= new Graph(environment);
 
-async function interactWithGraph() {
-    let public_follow_graph_schema_id = await graph.getSchemaIdFromConfig(environment, ConnectionType.Follow, PrivacyType.Public);
+    let public_follow_graph_schema_id = graph.getSchemaIdFromConfig(environment, ConnectionType.Follow, PrivacyType.Public);
 
     let connect_action: ConnectAction = {
         type: "Connect",
@@ -23,14 +23,17 @@ async function interactWithGraph() {
     let actions = [] as Action[];
     actions.push(connect_action);
 
-    let applied = await graph.applyActions(actions);
+    let applied = graph.applyActions(actions);
     console.log(applied);
 
-    let connections_including_pending = await graph.getConnectionsForUserGraph("1", public_follow_graph_schema_id, true);
+    let connections_including_pending = graph.getConnectionsForUserGraph("1", public_follow_graph_schema_id, true);
     console.log(connections_including_pending);
 
-    let exported = await graph.exportUpdates();
+    let exported = graph.exportUpdates();
     console.log(exported);
+
+    // always clean up the allocated memory in the end
+    graph.freeGraphState();
 }
-  
+
 interactWithGraph();