Floating header in JS

const header = document.getElementById('floating-header');
const title = document.getElementById('post-full-title');
const eventParams = { passive: true };

let lastScrollY = window.scrollY;
let ticking = false;

function requestTick() {
  if (ticking) return;
  requestAnimationFrame(update);
  ticking = true;
}

function update() {
  // show/hide floating header
  if (title.getBoundingClientRect().bottom < 0) {
    header.classList.add('floating-active');
  } else {
    header.classList.remove('floating-active');
  }

  ticking = false;
}

window.addEventListener('scroll', onScroll, eventParams);
function onScroll() {
  lastScrollY = window.scrollY;
  requestTick();
}

window.addEventListener('resize', requestTick, eventParams);
update();