Javascript function to add an "active" class on a DOM element during scroll over [param]

toggleActiveClassOnScroll.js

// HTML tag to listen
const header = document.querySelector("[data-header]");

const toggleActiveClassOnScroll = (elem) => {
  window.addEventListener("scroll", function () {
  window.scrollY >= 400 ? elem.classList.add("active") : elem.classList.remove("active");
  })
}

toggleActiveClassOnScroll(header)