YouTube Channel Hover Popup

Display a hover popup with channel info on YouTube after dynamic content load, with immediate loading indicator

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 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.

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

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         YouTube Channel Hover Popup
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  Display a hover popup with channel info on YouTube after dynamic content load, with immediate loading indicator
// @author       @dmtri
// @match        https://www.youtube.com/*
// @grant        none
// @license MIT
// ==/UserScript==

(function() {
    'use strict';
    let policy = null

    const createPopup = () => {
        const popup = document.createElement('div');
        popup.style.position = 'fixed';
        popup.style.zIndex = '1000';
        popup.style.width = '300px';
        popup.style.background = 'white';
        popup.style.border = '1px solid black';
        popup.style.borderRadius = '8px';
        popup.style.padding = '16px';
        popup.style.boxShadow = '0 4px 6px rgba(0,0,0,0.1)';
        popup.style.display = 'none';
        popup.style.fontSize = '16px';
        document.body.appendChild(popup);
        return popup;
    };

    const popup = createPopup();

    const showLoadingPopup = (popup, x, y) => {
        policy = trustedTypes.createPolicy('default2', {
            createHTML: (string) => string, // Allow all HTML strings
        });

        popup.innerHTML = policy.createHTML('<strong>Loading...</strong>');
        popup.style.left = `${x}px`;
        popup.style.top = `${y}px`;
        popup.style.display = 'block';
    };

    const updatePopupContent = (popup, content) => {
        popup.innerHTML = policy.createHTML(content);
        const closeButton = document.createElement('button');
        closeButton.textContent = 'X';
        closeButton.style.position = 'absolute';
        closeButton.style.top = '5px';
        closeButton.style.right = '10px';
        closeButton.style.border = 'none';
        closeButton.style.background = 'none';
        closeButton.style.cursor = 'pointer';
        closeButton.style.color = '#333';
        closeButton.style.fontSize = '16px';
        closeButton.style.fontWeight = 'bold';
        closeButton.onclick = () => popup.style.display = 'none';
        popup.appendChild(closeButton);
    };

    const fetchChannelInfo = async (url) => {
        try {
            const response = await fetch(url);
            const html = await response.text();
            const parser = new DOMParser();
            const doc = parser.parseFromString(policy.createHTML(html), 'text/html');
            const meta = doc.querySelector('meta[property="og:description"]');
            const description = meta ? meta.getAttribute('content') : 'No description available.';
            return `<strong>Description:</strong> ${description}<br>`;
        } catch (error) {
            return 'Failed to load description.';
        }
    };

    const throttle = (func, limit) => {
        let lastFunc;
        let lastRan;
        return function() {
            const context = this;
            const args = arguments;
            if (!lastRan) {
                func.apply(context, args);
                lastRan = Date.now();
            } else {
                clearTimeout(lastFunc);
                lastFunc = setTimeout(function() {
                    if ((Date.now() - lastRan) >= limit) {
                        func.apply(context, args);
                        lastRan = Date.now();
                    }
                }, limit - (Date.now() - lastRan));
            }
        };
    };

    const observeDOM = () => {
        const observer = new MutationObserver((mutations, obs) => {
            setTimeout(() => {
                const channelElements = document.querySelectorAll('.ytd-channel-name#text-container');
                if (channelElements.length) {
                    init(channelElements);
                    obs.disconnect(); // Stop observing after successful initialization
                }
            }, 1000);
        });
        observer.observe(document.body, {
            childList: true,
            subtree: true
        });
        console.log('[YouTube Channel Hover Popup] - observeDOM')
    };

    const init = (channelElements) => {
        console.log('YouTube Channel Hover Popup - init', { channelElements } )
        channelElements.forEach(channelElement => {
            let popupTimeout;

            channelElement.addEventListener('mouseenter', async (e) => {
                clearTimeout(popupTimeout);
                popupTimeout = setTimeout(async () => {
                    const url = channelElement.querySelector('a').href;
                    showLoadingPopup(popup, e.clientX, e.clientY + 20);
                    const content = await fetchChannelInfo(url);
                    updatePopupContent(popup, content);
                }, 500);
            });

            channelElement.addEventListener('mouseleave', () => {
                clearTimeout(popupTimeout);
                popup.style.display = 'none';
            });

            const throttledMouseMove = throttle((e) => {
                if (popup.style.display !== 'none') {
                    popup.style.left = `${e.clientX}px`;
                    popup.style.top = `${e.clientY + 20}px`;
                }
            }, 100); // Update popup position at most every 100ms

            channelElement.addEventListener('mousemove', throttledMouseMove);
        });
    };

    setTimeout(() => {
        const channelElements = document.querySelectorAll('.ytd-channel-name#text-container');
        init(channelElements)
    }, 5000); // Start observing DOM for changes
        setTimeout(() => {
        observeDom()
    }, 15000); // Start observing DOM for changes
})();