JSFiddle - React, Tailwind, and code Playground

HTML

<button id="btn">
click
</button>

JavaScript

const btn = document.querySelector('#btn');
btn.focus();
btn.onclick = function (e) {
  console.log('click', e);
}
btn.onkeydown = function (e) {
  console.log('keydown', e);
}
btn.onkeypress = function (e) {
  console.log('keypress', e);
}
btn.onkeyup = function (e) {
  console.log('keyup', e);
}

setTimeout(() => {
  document.activeElement.dispatchEvent(new KeyboardEvent('keydown',{which: 32, keyCode: 32, key: ' ', code: 'Space'}));
  /* document.activeElement.dispatchEvent(new KeyboardEvent('keypress',{which: 32, keyCode: 32, key: ' ', code: 'Space'})); */
  setTimeout(() => {
    document.activeElement.dispatchEvent(new KeyboardEvent('keyup',{which: 32, keyCode: 32, key: ' ', code: 'Space'}));
  }, 200);
}, 200)