AOPS classroom notification sound

Beep when a new message div is created
当前为 2024-06-25 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name         AOPS classroom notification sound
// @namespace    http://tampermonkey.net/
// @version      0.21
// @description  Beep when a new message div is created
// @author       Shaun Wang
// @match        https://artofproblemsolving.com/classroom/room/*
// @grant        none
// ==/UserScript==


(function() {
    'use strict';

    // notification sound
    function notificationSound() {
    var context = new (window.AudioContext || window.webkitAudioContext)();
    var oscillator = context.createOscillator();
    var gainNode = context.createGain();

    oscillator.connect(gainNode);
    gainNode.connect(context.destination);

    oscillator.type = 'sine';

    // A (Shortened)
    oscillator.frequency.setValueAtTime(440, context.currentTime);
    gainNode.gain.setValueAtTime(1, context.currentTime);
    gainNode.gain.exponentialRampToValueAtTime(0.2, context.currentTime + 0.05);

    // E
    oscillator.frequency.setValueAtTime(659.25, context.currentTime + 0.4);
    gainNode.gain.setValueAtTime(0.2, context.currentTime + 0.4);
    gainNode.gain.exponentialRampToValueAtTime(0.00001, context.currentTime + 1);

    oscillator.start(context.currentTime);
    oscillator.stop(context.currentTime + 1);
    }

    // check if the new node has the required classes
    function isTargetNode(node) {
        return node.nodeType === 1 && node.classList.contains('styles_thread__3HaEQ') && node.classList.contains('styles_topTracked__wDRH_');
    }

    // mark existing messages to avoid triggering sound on them
    function markExistingMessages() {
        const existingMessages = document.querySelectorAll('.styles_thread__3HaEQ.styles_topTracked__wDRH_');
        existingMessages.forEach(message => {
            message.dataset.seen = 'true';
        });
    }

    // monitors the page
    var observer = new MutationObserver(function(mutationsList) {
        for (var mutation of mutationsList) {
            if (mutation.type === 'childList') {
                for (var addedNode of mutation.addedNodes) {
                    if (isTargetNode(addedNode) && !addedNode.dataset.seen) {
                        addedNode.dataset.seen = 'true';
                        notificationSound();
                    }
                }
            }
        }
    });

    // mark existing messages and start observing for new ones
    window.addEventListener('load', function() {
        markExistingMessages();
        observer.observe(document.body, { childList: true, subtree: true });
    });
})();