feat: add renderable event to CoreNode (#676)

Author: wouterlucas

src/common/CommonTypes.ts

@@ -82,6 +82,14 @@ export type NodeTextureFreedPayload = {
   type: 'texture';
 };
 
+/**
+ * Payload for when node renderable status changes
+ */
+export type NodeRenderablePayload = {
+  type: 'renderable';
+  isRenderable: boolean;
+};
+
 /**
  * Combined type for all failed payloads
  */
@@ -105,6 +113,14 @@ export type NodeFailedEventHandler = (
   payload: NodeFailedPayload,
 ) => void;
 
+/**
+ * Event handler for when the renderable status of a node changes
+ */
+export type NodeRenderableEventHandler = (
+  target: any,
+  payload: NodeRenderablePayload,
+) => void;
+
 export type NodeRenderStatePayload = {
   type: 'renderState';
   payload: CoreNodeRenderState;

src/core/CoreNode.test.ts

@@ -198,5 +198,54 @@ describe('set color()', () => {
       node.update(0, clippingRect);
       expect(node.isRenderable).toBe(false);
     });
+
+    it('should emit renderable event when isRenderable status changes', () => {
+      const node = new CoreNode(stage, defaultProps);
+      const eventCallback = vi.fn();
+
+      // Listen for the renderableChanged event
+      node.on('renderable', eventCallback);
+
+      // Set up node as a color texture that should be renderable
+      node.alpha = 1;
+      node.x = 0;
+      node.y = 0;
+      node.width = 100;
+      node.height = 100;
+      node.color = 0xffffffff;
+
+      // Initial state should be false
+      expect(node.isRenderable).toBe(false);
+      expect(eventCallback).not.toHaveBeenCalled();
+
+      // Update should make it renderable (false -> true)
+      node.update(0, clippingRect);
+      expect(node.isRenderable).toBe(true);
+      expect(eventCallback).toHaveBeenCalledWith(node, {
+        type: 'renderable',
+        isRenderable: true,
+      });
+
+      // Reset the mock
+      eventCallback.mockClear();
+
+      // Make node invisible (alpha = 0) to make it not renderable (true -> false)
+      node.alpha = 0;
+      node.update(1, clippingRect);
+      expect(node.isRenderable).toBe(false);
+      expect(eventCallback).toHaveBeenCalledWith(node, {
+        type: 'renderable',
+        isRenderable: false,
+      });
+
+      // Reset the mock again
+      eventCallback.mockClear();
+
+      // Setting same value shouldn't trigger event
+      node.alpha = 0;
+      node.update(2, clippingRect);
+      expect(node.isRenderable).toBe(false);
+      expect(eventCallback).not.toHaveBeenCalled();
+    });
   });
 });

src/core/CoreNode.ts

@@ -38,6 +38,7 @@ import type {
   NodeTextureFailedPayload,
   NodeTextureFreedPayload,
   NodeTextureLoadedPayload,
+  NodeRenderablePayload,
 } from '../common/CommonTypes.js';
 import { EventEmitter } from '../common/EventEmitter.js';
 import {
@@ -1515,7 +1516,16 @@ export class CoreNode extends EventEmitter {
    * @param isRenderable - The new renderable state
    */
   setRenderable(isRenderable: boolean) {
+    const previousIsRenderable = this.isRenderable;
     this.isRenderable = isRenderable;
+
+    // Emit event if renderable status has changed
+    if (previousIsRenderable !== isRenderable) {
+      this.emit('renderable', {
+        type: 'renderable',
+        isRenderable,
+      } satisfies NodeRenderablePayload);
+    }
   }
 
   /**