tarinai/js/event_bus.js

"use strict";

class TarinaiEventBus {
  constructor() {
    this.handlers = new Map();
  }

  on(type, handler) {
    if (!type || typeof handler !== "function") return () => {};
    let list = this.handlers.get(type);
    if (!list) {
      list = new Set();
      this.handlers.set(type, list);
    }
    list.add(handler);
    return () => this.off(type, handler);
  }

  off(type, handler) {
    const list = this.handlers.get(type);
    if (!list) return;
    list.delete(handler);
    if (!list.size) this.handlers.delete(type);
  }

  emit(type, detail = {}) {
    if (!type) return null;
    const event = { type, detail: detail || {}, at: performance?.now?.() ?? Date.now() };
    const direct = this.handlers.get(type);
    if (direct) for (const handler of [...direct]) this.safeCall(handler, event);
    const wildcard = this.handlers.get("*");
    if (wildcard) for (const handler of [...wildcard]) this.safeCall(handler, event);
    return event;
  }

  safeCall(handler, event) {
    try { handler(event); }
    catch (err) { console.error("event handler failed", event.type, err); }
  }
}

window.TarinaiEvents = window.TarinaiEvents || new TarinaiEventBus();