Slack Bidirectional Text (Add RTL support to slack)

slack-auto-dir.user.js

// ==UserScript==
// @name         Slack Bidirectional Text (Add RTL support to slack)
// @namespace    http://bit.ly/2kHm59H
// @version      1.0
// @description  Set auto direction for all message boxes
// @author       Shahin
// @include     https://*.slack.com/*
// @grant        none
// ==/UserScript==
(function() {
    'use strict';

    const observer = new MutationObserver((mutations) => {
        document.querySelectorAll('span.message_body, textarea#msg_input').forEach((item)=>{item.setAttribute('dir', 'auto');});
    });

    // Notify me of everything!
    const observerConfig = {
        attributes: true,
        childList: true,
        characterData: true
    };

    var targetNode = document.body;
    observer.observe(targetNode, observerConfig);

})();

How does it work? dude