const findVowels = str => {
let count = 0
const vowels = ['а', 'я', о', 'ё', 'у', 'ю', 'э', 'е', 'и', 'ы']
for(let char of str.toLowerCase()) {
if(vowels.includes(char)) {
count++
}
}
return count
}

const xhr = new XMLHttpRequest();

xhr.open('GET', 'https://api.example.com/data');

xhr.onreadystatechange = () => {
if (xhr.readyState === XMLHttpRequest.DONE) {
console.log(xhr.responseText);
}
};

xhr.send();

const fetchData = (callback) => {
setTimeout(() => {
callback('Data fetched!');
}, 1000);
};

fetchData(data => {
console.log(data);
});