update

dist/js/utils/simpleEventEmitter.js

@@ -0,0 +1,40 @@
+export class SimpleEventEmitter {
+  constructor(logger = null) {
+    this.logger = typeof logger === "function" ? logger : null;
+    this.listeners = new Map();
+  }
+
+  on(eventName, handler) {
+    if (typeof handler !== "function") {
+      return () => {};
+    }
+    if (!this.listeners.has(eventName)) {
+      this.listeners.set(eventName, new Set());
+    }
+    const handlers = this.listeners.get(eventName);
+    handlers.add(handler);
+    return () => {
+      handlers.delete(handler);
+      if (!handlers.size) {
+        this.listeners.delete(eventName);
+      }
+    };
+  }
+
+  emit(eventName, detail) {
+    const handlers = this.listeners.get(eventName);
+    if (!handlers || !handlers.size) {
+      return;
+    }
+
+    for (const handler of Array.from(handlers)) {
+      try {
+        handler(detail);
+      } catch (error) {
+        if (this.logger) {
+          this.logger(`Listener for "${eventName}" threw`, error);
+        }
+      }
+    }
+  }
+}