Initial commit — Meridian OS browser desktop demo

js/core/bus.js

@@ -0,0 +1,36 @@
+/**
+ * Simple pub/sub event bus.
+ * on(evt, cb) - subscribe
+ * emit(evt, data) - publish
+ */
+const Bus = (() => {
+  const listeners = new Map();
+
+  return {
+    on(evt, cb) {
+      if (!listeners.has(evt)) listeners.set(evt, new Set());
+      listeners.get(evt).add(cb);
+      return () => this.off(evt, cb);
+    },
+
+    off(evt, cb) {
+      const set = listeners.get(evt);
+      if (set) {
+        set.delete(cb);
+        if (set.size === 0) listeners.delete(evt);
+      }
+    },
+
+    emit(evt, data) {
+      const set = listeners.get(evt);
+      if (set) {
+        for (const cb of set) {
+          try { cb(data); } catch (e) { console.error(`Bus emit error (${evt}):`, e); }
+        }
+      }
+    }
+  };
+})();
+
+export default Bus;
+export { Bus };