ENHANCEMENT added ConsoleSub node

README.md

@@ -133,19 +133,22 @@ const { errors, warnings } = await window.ir.validate(ir);
 console.log({ issues, errors, warnings });
 ```
 
-### Runtime bridge & ArrowKey publisher smoke test
+### Runtime bridge smoke test (ArrowKeyPub + ConsoleSub)
 
 The preload now exposes `window.runtime` alongside the runner and IR bridges. With the dev app running:
 
 ```js
 typeof window.runtime; // "object"
-const id = window.runtime.create("ArrowKeyPub", { topic: "keys/arrows" });
-window.runtime.start(id);
+const pubId = window.runtime.create("ArrowKeyPub", { topic: "keys/arrows" });
+const subId = window.runtime.create("ConsoleSub", { topic: "keys/arrows" });
+window.runtime.start(pubId);
+window.runtime.start(subId);
 // Press arrow keys while the Electron window is focused:
 // [publish] keys/arrows <- { key: "left", ts: ... }
-// [node:ArrowKeyPub_1] pressed: left
-window.runtime.stop(id);
-window.runtime.list(); // ["ArrowKeyPub_1"]
+// [node:ConsoleSub_1] received from ArrowKeyPub_1: {"key":"left","ts":...}
+window.runtime.stop(subId);
+window.runtime.stop(pubId);
+window.runtime.list(); // ["ArrowKeyPub_1", "ConsoleSub_1"]
 ```
 
 If `window.runtime` is missing, run `pnpm --filter ./apps/desktop-app build:main` again to regenerate the preload bridges.

apps/desktop-app/src/renderer/runtime/nodes/ConsoleSub.ts

@@ -0,0 +1,42 @@
+import type { NodeContext, NodeInstance, Publish } from "@bros2/runtime";
+
+type ConsoleSubConfig = {
+  topic?: string;
+  format?: (payload: Publish["data"]) => string;
+};
+
+/** Subscribes to a topic and logs inbound messages via ctx.log. */
+export class ConsoleSub implements NodeInstance {
+  id: string;
+  private ctx: NodeContext;
+  private topic: string;
+  private handler?: (evt: Publish) => void;
+  private format: (payload: Publish["data"]) => string;
+
+  constructor(ctx: NodeContext, config: ConsoleSubConfig = {}) {
+    this.id = ctx.id;
+    this.ctx = ctx;
+    this.topic = config.topic ?? "keys/arrows";
+    this.format =
+      config.format ??
+      ((payload) => (typeof payload === "string" ? payload : JSON.stringify(payload)));
+  }
+
+  start() {
+    if (this.handler) return;
+
+    this.ctx.log(`subscribing to "${this.topic}"`);
+    this.handler = (evt: Publish) => {
+      const message = this.format(evt.data);
+      this.ctx.log(`received from ${evt.from}: ${message}`);
+    };
+    this.ctx.bus.on(this.topic, this.handler);
+  }
+
+  stop() {
+    if (!this.handler) return;
+    this.ctx.bus.off(this.topic, this.handler);
+    this.handler = undefined;
+    this.ctx.log(`stopped subscribing to "${this.topic}"`);
+  }
+}

apps/desktop-app/src/renderer/runtime/registry.ts

@@ -4,11 +4,13 @@
 import { Runtime } from "@bros2/runtime";
 import type { NodeContext, NodeInstance } from "@bros2/runtime";
 import { ArrowKeyPub } from "./nodes/ArrowKeyPub";
+import { ConsoleSub } from "./nodes/ConsoleSub";
 
 type Factory = (ctx: NodeContext, config?: any) => NodeInstance;
 
 export const registry: Record<string, Factory> = {
   ArrowKeyPub: (ctx, config) => new ArrowKeyPub(ctx, config),
+  ConsoleSub: (ctx, config) => new ConsoleSub(ctx, config),
 };
 
-export const runtime = new Runtime(registry);
+export const runtime = new Runtime(registry);

apps/desktop-app/src/shared/runtime/registry.ts

@@ -1,8 +1,10 @@
 import { Runtime, type NodeFactory } from "@bros2/runtime";
 import { ArrowKeyPub } from "../../renderer/runtime/nodes/ArrowKeyPub";
+import { ConsoleSub } from "../../renderer/runtime/nodes/ConsoleSub";
 
 export const registry: Record<string, NodeFactory> = {
-  ArrowKeyPub: (ctx, config) => new ArrowKeyPub(ctx, config)
+  ArrowKeyPub: (ctx, config) => new ArrowKeyPub(ctx, config),
+  ConsoleSub: (ctx, config) => new ConsoleSub(ctx, config),
 };
 
 export const runtime = new Runtime(registry);