JSFiddle - React, Tailwind, and code Playground

HTML

<table><tr>
<td>dsdas ds
<td>-
<td>dd-
<td> 
<td>dsa
<td>ds
<td>-=
<td>--

JavaScript

var emptyTar = document.getElementsByTagName("td");

for (var i = 0; i < emptyTar.length; i++) {
    if (emptyTar[i].innerHTML.indexOf('-') === -1) {
        emptyTar[i].style.fontWeight = 'bold';
    }
}