transform in singleton

packages/dev/core/src/FlowGraph/flowGraphEngine.ts

@@ -13,23 +13,34 @@ export class IFlowGraphEngineConfiguration {
     scene: Scene;
 }
 /**
- * The FlowGraphEngine class holds all of the existing flow graphs and is responsible for creating new ones.
+ * The FlowGraphEngine singleton class holds all of the existing flow graphs and is responsible for creating new ones.
  * It also handles communication between them through an Event Coordinator
  */
 export class FlowGraphEngine {
     private readonly _eventCoordinator: FlowGraphEventCoordinator;
     private readonly _flowGraphs: FlowGraph[] = [];
+    /**
+     * The instance of the flow graph engine
+     */
+    private static instance: FlowGraphEngine;
 
-    constructor(private _config: IFlowGraphEngineConfiguration) {
+    private constructor() {
         this._eventCoordinator = new FlowGraphEventCoordinator();
     }
 
+    public static getInstance(): FlowGraphEngine {
+        if (!FlowGraphEngine.instance) {
+            FlowGraphEngine.instance = new FlowGraphEngine();
+        }
+        return FlowGraphEngine.instance;
+    }
+
     /**
      * Creates a new flow graph and adds it to the list of existing flow graphs
      * @returns a new flow graph
      */
-    createGraph(): FlowGraph {
-        const graph = new FlowGraph({ scene: this._config.scene, eventCoordinator: this._eventCoordinator });
+    createGraph(scene: Scene): FlowGraph {
+        const graph = new FlowGraph({ scene, eventCoordinator: this._eventCoordinator });
         this._flowGraphs.push(graph);
         return graph;
     }