Fix text direction for RTL articles on Pocket and file previews on GitHub and GitLab

auto_rtl.js

// ==UserScript==
// @name         Auto-RTL
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Fixes layout direction (RTL/LTR) for text on various websites
// @author       You
// @match        https://gitlab.com/*
// @match        https://github.com/*
// @match        http*://getpocket.com/beta/read/*
// @match        http*://getpocket.com/read/*
// @grant        none
// ==/UserScript==
/* jshint -W097 */
'use strict';

(function fixPreviews() {
    const rtl = /[\u060C-\u06FE\uFB50-\uFEFC]/gi;

    function dir(text, threshold) {
        threshold = threshold || 0.2;
        const matches = text.match(rtl);
        const count = matches ? matches.length : 0;
        return count / text.length > threshold ? 'rtl' : 'ltr';
    }

    const setDir = (node) => {
        switch (node.nodeName) {
            case 'CODE':
            case 'PRE':
                node.setAttribute('dir', 'ltr');
                break;
            default:
                var r = dir(node.textContent.substring(0, 100));
                node.setAttribute('dir', r);
                if (r === 'rtl') {
                    node.style.textAlign = 'right';
                }
                return;
        }
    };

    var target = document.body;
    var observer = new MutationObserver(function() {
        document.querySelectorAll('.file-content.wiki *, .markdown-body *, .reader_content *').forEach(setDir);
    });

    var config = { attributes: false, childList: true, characterData: true };

    observer.observe(target, config);
})();