A Tampermonkey script to hide messages from blocked users in Telegram group chats (works in Telegram Web Version K)

telegram_message_block.user.js

// ==UserScript==
// @name         Telegram Block Chat Message
// @namespace    https://github.com/lyc8503
// @version      2026-02-08
// @description  Block annoying users' messages everywhere (e.g. in Groups, Channels); Middle click someone's avatar to add to blocklist
// @author       lyc8503
// @match        https://web.telegram.org/*
// @grant        GM_registerMenuCommand
// ==/UserScript==

(function() {
    'use strict';

    const KEY = 'telegram_block_list';
    const getList = () => { try { return JSON.parse(localStorage.getItem(KEY) || '[]'); } catch { return []; } };
    const setList = (l) => localStorage.setItem(KEY, JSON.stringify([...new Set(l)]));

    const process = () => {
        const list = getList();

        document.querySelectorAll('.bubbles-group-avatar-container').forEach(container => {
            const idDiv = container.querySelector('[data-peer-id]');
            if (!idDiv) return;
            const uid = idDiv.dataset.peerId;

            // Hide already blocked users' message bubble
            if (list.includes(uid)) {
                const group = container.closest('.bubbles-group');
                if (group) group.style.display = 'none';
            }

            // Middle click listener
            if (!container.dataset.hasBlockListener) {
                container.dataset.hasBlockListener = '1';

                container.addEventListener('mousedown', function(e) {
                    if (e.button === 1) {
                        e.preventDefault();
                        e.stopPropagation();

                        if (confirm(`Block User ID: ${uid}?`)) {
                            setList([...getList(), uid]);
                            const group = container.closest('.bubbles-group');
                            if (group) group.style.display = 'none';
                        }
                    }
                }, { capture: true });
            }
        });
    };

    GM_registerMenuCommand('Manage blocklist', () => {
        const input = prompt('Current blocked users:', JSON.stringify(getList()));
        if (input) {
            try { setList(JSON.parse(input)); location.reload(); } catch { alert('Invalid JSON format'); }
        }
    });

    new MutationObserver(process).observe(document.body, { childList: true, subtree: true });
})();