This is the Typed Event Target library you are looking for.

import { TypedEventTarget } from "@worker-tools/typed-event-target";

// Can use custom event maps:
class Foo extends TypedEventTarget<{ 
  "error": ErrorEvent
  "custom": CustomEvent<string>
}> {
  /* ... */
}

// Enjoy correctly typed event here:
const foo = new Foo()
foo.addEventListener("error", ev => { /* ev: ErrorEvent */ })
foo.addEventListener("custom", ev => { /* ev: CustomEvent<string> */ })
foo.addEventListener("unknown", ev => { /* ev: Event */})

// Can use built-in event maps from e.g. lib.dom.d.ts:
class WorkerLike extends TypedEventTarget<WorkerEventMap> { /* ... */ }

// Can be used as a type:
type WindowLike = TypedEventTarget<WindowEventMap>;

// Uses built-in EventTarget:
foo instanceof EventTarget // => true

// No intermediate classes:
Object.getPrototypeOf(Foo.prototype) === EventTarget.prototype // => true

// Exports helper types in case you need them:
import type { 
  TypedEventListener, 
  TypedEventListenerObject, 
  TypedEventListenerOrEventListenerObject
} from "@worker-tools/typed-event-target"

This module is part of the Worker Tools collection
⁕

Worker Tools are a collection of TypeScript libraries for writing web servers in Worker Runtimes such as Cloudflare Workers, Deno Deploy and Service Workers in the browser.

If you liked this module, you might also like:

• 🧭 Worker Router --- Complete routing solution that works across CF Workers, Deno and Service Workers
• 🔋 Worker Middleware --- A suite of standalone HTTP server-side middleware with TypeScript support
• 📄 Worker HTML --- HTML templating and streaming response library
• 📦 Storage Area --- Key-value store abstraction across Cloudflare KV, Deno and browsers.
• 🆗 Response Creators --- Factory functions for responses with pre-filled status and status text
• 🎏 Stream Response --- Use async generators to build streaming responses for SSE, etc...
• 🥏 JSON Fetch --- Drop-in replacements for Fetch API classes with first class support for JSON.
• 🦑 JSON Stream --- Streaming JSON parser/stingifier with first class support for web streams.

Worker Tools also includes a number of polyfills that help bridge the gap between Worker Runtimes:

• ✏️ HTML Rewriter --- Cloudflare's HTML Rewriter for use in Deno, browsers, etc...
• 📍 Location Polyfill --- A Location polyfill for Cloudflare Workers.
• 🦕 Deno Fetch Event Adapter --- Dispatches global fetch events using Deno’s native HTTP server.

Fore more visit workers.tools.