JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<div id="theDiv" style="width:200px; border:1px solid red;">
  <span id="text" style="display:none;white-space:nowrap;">This sentence is too large to fit within the div.</span>
</div>

JavaScript

var divWidth = $("#theDiv").width();
var text = $("#text");
var fontSize = 12;

while (text.width() > divWidth)
  text.css("font-size", fontSize -= 0.5);

text.css("display", "inline");