JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="left">
  <li>Menu item 1</li>
  <li>Menu item 2</li>
  <li>Menu item 3</li>
</ul>

<br class="clearFloat" />

<button onClick={togglePosition()}>Change position</button>

CSS

.left {
  float: left;
}

.right {
  float: right;
}

.clearFloat {
  clear: both;
  margin: 0;
  padding: 0
}

button {
  display: block;
}

JavaScript

togglePosition = () => {
	const menu = document.querySelector('ul')
  if(menu.className == 'left') {
  	menu.className = 'right';
  } else {
  	menu.className = 'left';
  }
}