JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://github.com/downloads/SteveSanderson/knockout/knockout-2.1.0.js"></script>
<div id="VMDiv">    
<table>
   <thead>
      <tr>
         <th>Raw</th>
         <th>Formatted</th>
      </tr>
   </thead>
   <tbody>
       <tr>
          <td data-bind="text : SomeData "> </td>
          <td data-bind="text : formatPercent(SomeData())"> </td>
       </tr>
    </tbody>
</table>
</div>

JavaScript

function formatPercent(value) {
    return value.toFixed(2) + "%";
}

function vm() {
    var self = this;
    self.SomeData = ko.observable(62.1795972898);
}

ko.applyBindings(new vm(), document.getElementById("VMDiv"));