JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgit.com/bgrins/TinyColor/master/tinycolor.js"></script>
<div style="background-color:red;">red</div>
<div style="background-color:black;">black</div>
<div style="background-color:white;">white</div>
<div style="background-color:#220000;">220000</div>
<div style="background-color:#ee9999;">ee9999</div>
<div style="background-color:#e4d92a ;">e4d92a </div>
<div style="background-color:#5eeed4 ;">5eeed4 </div>
<div style="background-color:#956df8 ;">956df8 </div>
<div style="background-color:#6728a4  ;">6728a4  </div>

JavaScript

// TinyColor text example for http://stackoverflow.com/questions/28687534/finding-dark-light-colors
// 
// Uses https://github.com/bgrins/TinyColor
//
$(function() {
    $('div').each(function(e) {
        var c = tinycolor($(this).css('background-color'));
        if (c.isDark()) {
            $(this).css('color',c.lighten(50));
            $(this).text($(this).text() + ' (dark)');
        } else {
            $(this).css('color',c.darken(50));
            $(this).text( $(this).text() + ' (light)');
        }
    });
});