JSFiddle - React, Tailwind, and code Playground

HTML

<p id="foo">&nbsp;</p>

<button onclick="
  document.getElementById('foo').innerHTML = nextWord();
">Update</button>
<button onclick="
  document.getElementById('foo').innerHTML = lastWord();
">last</button>

JavaScript

var wordArray = ['fe','fi','fo','fum'];
var count = -1;
var nextWord = (function() {
  
  return function() {
    return wordArray[++count % wordArray.length];
  }
}());
var lastWord = (function() {

            return function() {
            return wordArray[--count % wordArray.length];
            }
    
}());