Why does getVoices work every other time?

Question

JavaScript

I call:

window.speechSynthesis.getVoices(); // пустой массив

You need to get an array of vote objects.
As soon as I did it, it worked, after 5-10 page updates it stopped (both on document.readyand on window.onload).
What is the problem?
Task: check browser support and check for ru-RU voice

Answer 1

Decided so far:

window.speechSynthesis.addEventListener('voiceschanged', function() {
  if(isSpeechSynthesis() && isRuVoices()) {
    $('.voice').toggleClass('d-none');
  }
});

function isSpeechSynthesis() {
  return window.speechSynthesis || false;
}

function isRuVoices() {
  const arrVoices = window.speechSynthesis.getVoices();
  return arrVoices.find(function(item){
    return item.lang === 'ru-RU';
  });
}