// Created on savesnippets.com · https://savesnippets.com/Wqb5g9Zc8dmtAI
function animateCounter(element, from, to, duration = 1000, easing = (t) => t * (2 - t)) {
  const start = performance.now();
  function update(now) {
    const t = Math.min((now - start) / duration, 1);
    element.textContent = Math.round(from + (to - from) * easing(t)).toLocaleString();
    if (t < 1) requestAnimationFrame(update);
  }
  requestAnimationFrame(update);
}

// Usage
const el = document.querySelector('#counter');
animateCounter(el, 0, 1_234_567, 2000);