Tapermonkey script to clean up YouTube titles - Formats fully capitalised words and removes spaces in front of question marks and exclamation marks.

clean_youtube_titles.js

// ==UserScript==
// @name         Clean YouTube Titles
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Cleans up YouTube titles by formatting fully capitalised words and removing spaces in front of question marks and exclamation marks.
// @author       Tancred and ChatGPT :)
// @match        https://www.youtube.com/*
// @grant        none
// @require      https://cdn.jsdelivr.net/gh/CoeJoder/waitForKeyElements.js@v1.2/waitForKeyElements.js
// ==/UserScript==

(function() {
    'use strict'

    /////////////// SETTINGS (FEEL FREE TO ADJUST THEM TO YOUR NEEDS) ///////////////

    // Set to "true" to print all converted words in your browser's console. You can filter the console by "Clean YouTube Titles"
    const isDebug = false // Default: false

    // How many milliseconds to wait until the next check. Increase the amount for better performance. Decrease it for faster formats.
    const interval = 300 // Default: 300

    // The whitelist of words that will not be formatted.
    const whitelist = [
        // Roman Numerals
        'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', 'X', 'XI', 'XII', 'XIII', 'XIV', 'XV', 'XVI', 'XVII', 'XVIII', 'XIX', 'XX',
        // Often used abbreviations in YouTube titles
        'HD', 'HQ',
        // Content specific abbreviations
        'ASMR', 'SMP', 'PVP', 'DIY', 'MMO', 'MMORPG', 'MOBA', 'AI', 'IRL', 'GCI',
        // PC abbreviations
        'PC', 'LAN', 'WIFI', 'WLAN', 'RAM', 'CPU', 'GPU', 'RTX', 'GTX', 'XP',
        // Video game initals and terms
        'GTA', 'FFXIV', 'WOW', 'EO', 'TESO', 'ESO',
        // Company and channel initials or related terms
        'WBS', 'CEO', 'YOASOBI', 'NNO',
    ]

    /////////////// DO NOT TOUCH UNLESS YOU KNOW WHAT YOU ARE DOING ///////////////

    // Format titles on front page, subscription page, recommended videos panel, etc.
    waitForKeyElements("#video-title", formatVideoTitles, false, interval)

    // Format titles when video is opened
    waitForKeyElements("h1.ytd-watch-metadata", formatVideoTitles, false, interval)

    // Format the video title in the browser tab
    setInterval(() => { document.title = format(document.title) }, interval)

    function formatVideoTitles(jNode) {
        jNode.textContent = format(jNode.textContent)
    }

    function format(str) {
        // Capitalize all words in CAPS, except whitelisted ones.
        const words = str.match(/\b[A-Z]{2,}\b/g) ?? []

        for (const word of words) {
            if (whitelist.includes(word)) {
                continue
            }

            const newWord = word.substring(0, 1).toUpperCase() + word.substring(1).toLowerCase()
            str = str.replaceAll(word, newWord)

            if (isDebug) {
                console.debug(`%c[Clean YouTube Titles] %c[DEBUG] %c${word} → ${newWord}`, 'color: orange', 'color: aqua', 'color: inherit')
            }
        }

        // Remove spaces before question marks and exclamation marks
        str = str.replace(/\s+([?!])/g, '$1')

        return str
    }
})();