hide-already-watched-recs.js

// ==UserScript==
// @name         Hide already watched YouTube videos
// @version      0.1
// @description  Hide already watched recommended YouTube videos from the home page
// @match        https://www.youtube.com
// ==/UserScript==

(function() {
    'use strict';

    (function() {
    'use strict';

    var found;

    var interval = setInterval(function() {
        var recommendation = document.querySelector('ytd-thumbnail-overlay-resume-playback-renderer [style="width: 100%;"]:not([clicked])');

        if (!recommendation) {
            return;
        }

        var button = recommendation.parentNode?.parentNode?.parentNode?.parentNode?.parentNode?.querySelector('[aria-label="Action menu"]');

        if (!button) {
            return;
        }

        recommendation.setAttribute('clicked', 'clicked');

        button.click();

        setTimeout(function() {
            document.querySelectorAll('[role="menuitem"]')[4].click();
        }, 250);
    }, 500);
})();


})();