喵喵喵

// ==UserScript==
// @name         喵喵喵
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  nyan
// @author       fkxr
// @match        *://*/*
// ==/UserScript==

(function() {
    'use strict';

    const targetRegex = /([，。？：！])/g;

    function processNode(node) {
        if (node.nodeType === Node.TEXT_NODE && node.textContent.trim() !== "") {
            const originalText = node.textContent;
            const newText = originalText.replace(targetRegex, '喵$1');
            if (newText !== originalText) {
                node.textContent = newText;
            }
        }
    }

    function walk(root) {
        const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, null, false);
        let node;
        while (node = walker.nextNode()) {
            processNode(node);
        }
    }

    walk(document.body);

    const observer = new MutationObserver((mutations) => {
        mutations.forEach((mutation) => {
            mutation.addedNodes.forEach((node) => {
                if (node.nodeType === Node.TEXT_NODE) {
                    processNode(node);
                } else {
                    walk(node);
                }
            });
        });
    });

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