fix: graph are not drawn

src/01-bezierCurves/CurveHelper.ts

@@ -121,6 +121,10 @@ class CurveHelperBernstein implements PipelineObserver, PipelineRenderable, Pipe
             new THREE.MeshBasicMaterial({ color: 0xffffff, opacity: 0.5, transparent: true }));
         this._background.position.z = offset;
 
+        // initialize here to avoid null reference => does not show in inspector
+        this.initGraphs();
+        this.initPoints();
+
         this._group = new THREE.Group();
         this._group.add(this._background);
         this._group.add(this._xAxis.object());
@@ -133,9 +137,6 @@ class CurveHelperBernstein implements PipelineObserver, PipelineRenderable, Pipe
         this._yAxis._object3d.parent = this._background;
         this._graphs.forEach((graph) => { graph._object3d.parent = this._background; });
         this._point.forEach((point) => { point._object3d.parent = this._background; });
-
-        this.initGraphs();
-        this.initPoints();
     }
 
     private initGraphs(): void {