links.forEach(a=> {
    a.onclick = () => {
        links.forEach(a=>a.classList.remove('active'));
        a.classList.add("active");
    }
})

向每个元素添加事件，然后单击链接执行类的添加/删除。

var navElements = document.querySelectorAll('a');
      //looping through each anchor element
      navElements.forEach(function(element){
           //adding click event on each anchor element
            element.addEventListener('click',function(e){
                 //stop default behaviour
                 e.preventDefault();
                 //select current active element
                 let active = document.querySelector('.selected');
                 active?.classList.remove('selected'); //remove class  
                 this.classList.add('selected'); //add class to current click element
      });
});