JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<button>0</button> 
<button class="btn btn-primary">1 </button> 
<button class="btn btn-danger">2</button> 
<button class="btn btn-dark">3</button> 
<button class="btn btn-warning">4</button>

JavaScript

//get all buttons
let buttons = document.querySelectorAll('button')

//Original buttons
console.log(buttons);

//store
var copybtns = [];

//foreach
buttons.forEach((data) => copybtns.push(data))

//log the array data
console.log(copybtns);