Waits for an element using the MutationObserver API
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/523012/1519437/WaitForKeyElement.js
// ==UserScript==
// @name WaitForKeyElement
// @namespace Violentmonkey Scripts
// @version 1.1
// @description Waits for an element using the MutationObserver API
// @author PaywallDespiser
// @grant none
// ==/UserScript==
/**
* Waits for a element of a given selector.
*
* @param {string} selector
* @param {Element} [target=document.body]
* @returns {Promise<Element>}
*/
function waitForKeyElement(selector, target = document.body) {
return new Promise((resolve) => {
{
const element = target.querySelector(selector);
if (element) {
return resolve(element);
}
}
const observer = new MutationObserver((mutations) => {
for (const mutation of mutations) {
for (const node of mutation.addedNodes) {
if (!(node instanceof HTMLElement)) continue;
if (node.matches(selector)) {
observer.disconnect();
resolve(node);
return;
}
const childElement = node.querySelector(selector);
if (childElement) {
observer.disconnect();
resolve(childElement);
return;
}
}
}
});
observer.observe(target, {
childList: true,
subtree: true,
attributes: false,
characterData: false,
});
});
}