JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div id="fill">
    sample
  </div>
</div>

CSS

#container {
  position: absolute;
  margin: 0;
  padding: 0;
  top: 0; bottom: 0; left: 0; right: 0;
  overflow: hidden;
}

#fill {
  margin: 0;
  display: inline-block;
  transform-origin: 0 0;
}

JavaScript

function fillWithText () {
	var fill = document.getElementById('fill');
	var container = document.getElementById('container');

	var totalHeight = container.clientHeight;
	var totalWidth = container.clientWidth;

	var currentHeight = fill.clientHeight;
	var currentWidth = fill.clientWidth;

	var scaleX = totalWidth / currentWidth;
	var scaleY = totalHeight / currentHeight;

	fill.style.transform = 'scale(' + scaleX + ',' + scaleY + ')';
};
window.addEventListener('resize', fillWithText, false);
fillWithText();