JSFiddle - React, Tailwind, and code Playground
HTML
<div>
<textarea cols="30" rows="10"></textarea>
</div>
<button>Select All</button>
JavaScript
const ta = document.querySelector('textarea');
const btn = document.querySelector('button');
btn.addEventListener('click', ev => {
console.log('click!', ev);
ta.select();
ta.dispatchEvent(new KeyboardEvent('keypress', { 'key': 'Backspace'}))
});