Scrolling JS with bug

windowOnScroll();
function windowOnScroll() {
  window.addEventListener("scroll", function(e){
    const {scrollHeight,scrollTop,clientHeight} = document.documentElement
    if (scrollTop + clientHeight > scrollHeight -5){
      if(document.querySelectorAll(".post-item").length < document.getElementById("total_count").value) {
        var lastId = document.querySelectorAll(".post-item");
        var lastchild = lastId[lastId.length-1];
        var id=lastchild.getAttribute("id");
        getMoreData(id);
      }
    }
  });
}
function getMoreData(id) {
  window.removeEventListener("scroll",windowOnScroll())
  document.querySelector('.ajax-loader').classList.remove("none");
  var formdata=new FormData();
  formdata.append("lastId",id);
  fetch('getMoreData.php',{
    method: 'POST',
    body:formdata
  }).then(function(response){
    response.text().then(function(result){
      setTimeout(function() {
        document.querySelector('.ajax-loader').classList.add("none");
        document.getElementById("post-list").innerHTML+=result;
        windowOnScroll();
      }, 1000);
    })
  }).catch(function(err){
    console.error(err);
  });
}