Toggle arrow error through javascript

JavaScript
4

thanks for suggestion, i tried it but code is not working

<script>  
const tabItems = document.querySelectorAll('[data-rel]')
const toggleActive = event => {
  event.currentTarget.classList.toggle('active')
}
const addToggleHandler = item => {
  item.addEventListener('click', toggleActive)
}
Array.from(tabItems).forEach(addToggleHandler)
</script>

css:
li.active::before {
transform: rotate(90deg);
}

.tabsSublist {
display: none;
}

li.active + .tabsSublist {
display: block;
}