JSFiddle - React, Tailwind, and code Playground

HTML

<table class="list">
   <tr class="8008"><td>1</td></tr>
   <tr class="8002"><td>2</td></tr>
   <tr class="8008"><td>3</td></tr>
   <tr class="8088"><td>4</td></tr>
   <tr class=""><td>NONE</td></tr>
   <tr class="8077"><td>asdas</td></tr>
   <tr class="8077"><td>asdasd</td></tr>
   <tr class="8077"><td>asdasd</td></tr>
</table>

CSS

.alert{
  background:red;
}

JavaScript

var arr1 = [];
    var arr2 = [];
    $(".list tr").each(function(){
    		arr1.push($(this).attr("class"));
    });
    console.log(arr1.length);
    $(".list tr").each(function(index){
    		var newArray = arr1.slice();
       	newArray.splice(index, 1); // remove index value from an array, so this index != match its own
 				console.log(newArray);
        if ($.inArray($(this).attr("class"), newArray ) !== -1)
        		$(this).addClass("alert");
        
    });