discord_debounce.js

javascript:(function(){
    const join_time = Date.now();
    function debounce_msg(m){
        m.style.visibility = Date.parse(m.querySelector("time").dateTime) < join_time ? "hidden" : "initial";
    }

    function debounce_msgs(records){
        document.querySelectorAll("ol[data-list-id='chat-messages']>li").forEach(debounce_msg);
    }
    let observer = new MutationObserver(debounce_msgs);
    observer.observe(document, {subtree: true, childList: true});
    debounce_msgs();
})();