RTL support for slack.com

slack_rtl_support.user.js

// ==UserScript==
// @name        RTL Slack
// @namespace   slask.com
// @include     https://*.slack.com/*
// @version     1.2.2
// @grant       none
// ==/UserScript==

function isRTL(text) {
  if (text !== "") {
    if ("اآبپتثجچحخدذرزژسشصضطظعغفقکگلمنوهیؤئيإأةك۰۱۲۳۴۵۶۷۸۹".indexOf(text[0]) > -1) {
      return true;
    }
  }
  return false;
}

var is_rtl = function(string) {
    // Function to check if String is RTL
    
    // match all unicode characters from ۹ to ؟
    re_rtl = /[؟-۹]/;
    // match other characters
    re_notRtl = /[^؟-۹]/;
    
    // remove html links/images from the text along with punctuations and ...
    var re_trim = /(<a\b.*?<\/a>)|(<img\b.*?src=\".*?\">)|[ !\.:\"\'#~@\*()\-+%$/\\{}\[\]<>\|]/g;
    var stringTrimmed = string.replace(re_trim,"");
    
    if (!stringTrimmed.match(re_rtl)) {
        // if there are no rtl characters:
        return false;
    }
    if (stringTrimmed[0].match(re_rtl)) {
       // if the first character is rtl, the text is most likely rtl.
       return true;
    }
    if (stringTrimmed.match(re_notRtl)){
        // if there are also nonRTL characters which characters are more?
        var sumRTL = 0;
        var sumLTR = 0;
        for (var idx = 0; idx < stringTrimmed.length; idx++) {
            if (stringTrimmed[idx].match(re_rtl)) {
                sumRTL += 1;
            }
            else {
                sumLTR += 1;
            }
        }
        if (sumRTL >= sumLTR) {
            return true;
        }
        return false;
    }
};

if ($ !== undefined) {
  $(document).ready(function() {
    
    var style = '<style type="text/css">';
    style += '.message_body.rtl { direction: rtl; }';
    style += '.rtl-input {direction: rtl;text-align: right;}';
    style += '.rtl:before {content: "\u202B";}';
    style += '.rtl:after {content: "\u200F";}';
    style += '.edited { float: right; }';
    style += '.text-rtl { direction: rtl; }';
    style += '.text-rtl li[type=bullet], .text-rtl li[type=number] { padding-right: 2rem; padding-left: 0; }';
    style += '.text-rtl li[type=bullet]:before, .text-rtl li[type=number]:before { margin-right: -61px; margin-left: 0; text-align: left; }';
    style += '</style>';


    $('head').append(style);
      
      $('#footer_msgs').bind('DOMNodeInserted', function(e) {
          $('.ql-editor').on('blur keyup paste input', function() {
              if (is_rtl($(this).html())) {
                  $(this).addClass('rtl-input');
              }
              else {
                  $(this).removeClass('rtl-input');
              }
          });
      });
      
    $('#msgs_div').bind('DOMNodeInserted', function(e) {
        
      $('.message_body').each(function() {
          if ( is_rtl( $(this).html() ) ) {
              $(this).addClass('rtl');
          }
      });
      
      $('#msg_text').focus(function() {
        if (is_rtl($(this).val())) {
          $(this).addClass('rtl-input');
        }
        else {
          $(this).removeClass('rtl-input');
        }
      });
    });

    $('ts-space .content').bind('DOMNodeInserted', function(e) {
      $('.text').each(function() {
          if ( is_rtl( $(this).find('.shadow').html() ) ) {
              $(this).addClass('text-rtl');
          }
      });
    });

  });
}

that is not 'RTL' support, but just persian support. there is another RTL languages like Hebrew.