Udemy Fast-forward bookmarklet

udemy_ff.js

javascript:(function forwarder(toggle_script_execution = false) {
    const start_alert = () => console.log("%c Forwarder script started running...", "color: green");
    const stop_alert  = () => console.log("%c Forwarder script stopped running!", "color: red");
    
    /* toggling the execution of this whole script */
    if(toggle_script_execution && 'ff_set' in window) {
        window.ff_set = !window.ff_set;
        if(window.ff_set) start_alert();
    } else if(!('ff_set' in window)) {
        window.ff_set = true;
        start_alert();
    }
    if(!window.ff_set) {
        if(toggle_script_execution) stop_alert();
        return;
    }

    /* time to wait for the video to load before moving to the end of the video */
    const VIDEO_LOAD_TIME = 9000;
    /* the duration to watch the video, for it to be considered 'watched', before moving to the next item in the course */
    const VIDEO_WATCH_TIME = 3000;
    /* the duration to read the article, for it to be considered 'read', before moving to the next item in the course */
    const ARTICLE_READ_TIME = 12000;
    /* time to wait for the exercise(non-lecture) to load before moving to the next item in the course */
    const EXERCISE_LOAD_TIME = 3000;

    function goToNextItem(is_gotoNext_button_available = true) {
        if (!window.ff_set) return;
        if(is_gotoNext_button_available) {
            document.getElementById('go-to-next-item')?.click();
            forwarder();
        } else {
            setTimeout(() => {
                document.querySelector('[data-purpose="go-to-next"].item-link')?.click();
                forwarder();
            }, EXERCISE_LOAD_TIME);    
        }
    }

    function getCurrentItem(){
        const get_li = () => document.querySelector('li[class*="curriculum-item-link--is-current"]');
        const fix1 = () => document.querySelector('div[data-purpose="curriculum-section-container"]')?.querySelectorAll('.ud-accordion-panel-toggler').forEach(x => x.click());
        const fix2 = () => document.querySelector('button[class*="course-content-toggle"].ud-heading-md')?.click();
        
        let li = get_li();
        if(li) return li;
        /* else */
        fix1();
        li = get_li();
        if(li) return li;
        /* else */
        fix2();
        li = get_li();
        if(li) return li;
        /* else */
        fix1();
        li = get_li();
        return li;
    }
    const currentItem = getCurrentItem();

    const icon_element = currentItem.firstElementChild.lastElementChild.lastElementChild.firstElementChild.firstElementChild.firstElementChild.firstElementChild;
    const icon_type = icon_element.getAttribute('xlink:href');

    const current_element_is_completed = currentItem.firstElementChild.firstElementChild.firstElementChild.firstElementChild.firstElementChild.checked;
    const current_element_is_not_a_lecture = !icon_type && icon_element?.nodeName.toUpperCase() == 'SPAN';
    if(current_element_is_completed || current_element_is_not_a_lecture) {
        goToNextItem(!current_element_is_not_a_lecture);
        return;
    }
    if(icon_type.endsWith('video')){
        setTimeout(() => {
            if (!window.ff_set) return;
            let video = document.querySelector('video');
            if(video.paused) video.play();
            const video_time = "0:" + document.querySelector('span[data-purpose="duration"]').textContent;
            const last_second_of_the_video = video_time.split(":").slice(-3).map(Number).reverse().reduce((t, x, i) => t + x * Math.pow(60, i), 0);
            video.currentTime = last_second_of_the_video - (VIDEO_WATCH_TIME + 2000) / 1000;
            console.log('video-item forwarded at:', last_second_of_the_video + "s");
        }, VIDEO_LOAD_TIME);
        setTimeout(goToNextItem, VIDEO_LOAD_TIME + VIDEO_WATCH_TIME);
    } else {
        setTimeout(goToNextItem, ARTICLE_READ_TIME);
    }
})(true);