Smart Text Justifier

Justifies everything unless they are centered or aligned to the right.
Ask a question, post a review, or report the script.
Wrap lines
// ==UserScript==
// @name         Smart Text Justifier
// @namespace    http://tampermonkey.net/
// @version      1.5
// @description  Justifies everything unless they are centered or aligned to the right.
// @author       Ȼaptain Jøhn “Søap” MacTavish
// @license      CC-BY-NC-SA-4.0
// @match        *://*/*
// @exclude      https://www.grok.com/*
// @exclude      https://www.chatgpt.com/*
// @grant        none
// ==/UserScript==


(
    function()
    {
        'use strict';

        const ProcessedElements = new WeakSet();

        const IgnoredTags = new Set
        ([
            'SCRIPT', 'STYLE', 'META', 'LINK', 'HEAD', 'TITLE', 'NOSCRIPT',
            'BR', 'HR', 'IMG', 'VIDEO', 'AUDIO', 'CANVAS', 'SVG', 'PATH',
            'IFRAME', 'OBJECT', 'EMBED', 'CODE', 'PRE', 'A', 'SPAN', 'BUTTON',
            'LABEL', 'INPUT', 'SELECT', 'H1', 'H2', 'H3', 'H4', 'H5', 'H6',
            'STRONG', 'B', 'I', 'EM', 'SMALL', 'SUB', 'SUP', 'KBD', 'ABBR',
            'CITE', 'DD', 'DT', 'NAV', 'HEADER', 'FOOTER'
        ]);

        const CheckAndQueueElement = (NodeToCheck, ElementsQueue) =>
        {
            if (!ProcessedElements.has(NodeToCheck) && !IgnoredTags.has(NodeToCheck.tagName))
            {
                ProcessedElements.add(NodeToCheck);

                const ComputedAlignment = window.getComputedStyle(NodeToCheck).textAlign;

                if (ComputedAlignment !== 'center' && ComputedAlignment !== 'right')
                {
                    ElementsQueue.push(NodeToCheck);
                }
            }
        };

        const ProcessElements = (Elements) =>
        {
            const ElementsToUpdate = [];

            // DOM READ PHASE: Prevents Layout Thrashing by batching all reads first.
            for (const Element of Elements)
            {
                if (Element.nodeType === 1)
                {
                    CheckAndQueueElement(Element, ElementsToUpdate);

                    const Children = Element.querySelectorAll('*');

                    for (const Child of Children)
                    {
                        CheckAndQueueElement(Child, ElementsToUpdate);
                    }
                }
            }

            // DOM WRITE PHASE: Applies styles without triggering style recalculations mid-loop.
            for (const Element of ElementsToUpdate)
            {
                Element.style.setProperty('text-align', 'justify', 'important');
                Element.style.setProperty('text-justify', 'inter-word', 'important');
            }
        };

        const InitializeObserver = () =>
        {
            const InitialElements = [ document.body ];
            ProcessElements(InitialElements);

            let PendingNodes = [];
            let IsProcessing = false;

            const ContentObserver = new MutationObserver
            (
                (Mutations) =>
                {
                    for (const Mutation of Mutations)
                    {
                        for (const Node of Mutation.addedNodes)
                        {
                            if (Node.nodeType === 1)
                            {
                                PendingNodes.push(Node);
                            }
                        }
                    }

                    if (!IsProcessing && PendingNodes.length > 0)
                    {
                        IsProcessing = true;

                        requestAnimationFrame
                        (
                            () =>
                            {
                                ProcessElements(PendingNodes);
                                PendingNodes = [];
                                IsProcessing = false;
                            }
                        );
                    }
                }
            );

            ContentObserver.observe
            (
                document.body,
                {
                    childList: true,
                    subtree: true
                }
            );
        };

        if (document.readyState === 'complete' || document.readyState === 'interactive')
        {
            InitializeObserver();
        }
        else
        {
            window.addEventListener('DOMContentLoaded', InitializeObserver);
        }
    }
)
();