9DB Raid Finder: Fix focus detection

Fixes the focus detection on the 9DB Pokémon GO Raid Finder

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(У мене вже є менеджер скриптів, дайте мені встановити його!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        9DB Raid Finder: Fix focus detection
// @namespace   m43v6blcjzeaiq6oh9
// @match       https://9db.jp/pokego/data/62
// @match       https://9db.jp/pokemongo/data/9906
// @grant       none
// @version     1.0
// @description Fixes the focus detection on the 9DB Pokémon GO Raid Finder
// @run-at      document-start
// @inject-into content
// @license     MIT
// ==/UserScript==

(function () {
	"use strict";

	const { CustomEvent } = window, { WeakSet } = globalThis;

	// Block blur/focus events on window,
	// except the fake ones we create
	const whitelistedEvents = new WeakSet();
	const filterEvents = (event) => {
		// .delete() returns true if the element was actually removed
		if (!whitelistedEvents.delete(event)) {
			event.stopImmediatePropagation?.();
		}
	};

	window.addEventListener("blur",  filterEvents, { passive: true });
	window.addEventListener("focus", filterEvents, { passive: true });

	// Convert visibility events to blur/focus events
	window.addEventListener("visibilitychange", function () {
		const fakeEvent = new CustomEvent((document.visibilityState === "hidden") ? "blur" : "focus");

		whitelistedEvents.add(fakeEvent);
		this.dispatchEvent(fakeEvent);
	});
})();