Jquery .last() equivalence to Javascript

Hi I’m converting Some jquery code to javascript.
what is I’m trying to convert is:

frame.contents().find("div[class='footNote']").remove();
               var last = frame.contents().find("div").last();

               _.each($scope.currencyNotes, function (item) {
                   var footNote = $("<div class='footNote' />");
                   footNote.css('font-size', '13px');
                   

                   var fFootNote =footNote.appendTo(last);
                   fFootNote.html("<div style='float:left;width:25px'>" + item.Id + "</div>" + " <div style='float:left;width:80%'>" + item.Text + "</div>");
               });

what have i can manage to convert by googling is

 frame.contentDocument.querySelector("div[class='footNote']").parentNode.removeChild(frame);
      var last = frame.contentDocument.querySelector("div").last();

      Array.from(this.currenyNotes).forEach((item:any) => {
        //todo
        var footNote = document.createElement("div class='footNote' ");
        footNote.style.fontSize = "13px";
       
        

        var fFootNote = footNote.appendChild(last);
        fFootNote.innerHTML("<div style='float:left;width:25px'>" + item.Id + "</div>" + " <div style='float:left;width:80%'>" + item.Text + "</div>");

I have some problem with converting .last().when i replaced with last with last = frame.contentDocument.querySelector("div").lastChild; or last = frame.contentDocument.querySelector("div").lastElementChild; it shows fFootNote.innerHTML error:Property ‘innerHTML’ does not exist on type ‘ChildNode’ .

if i convert .last() with i replaced with last with last = frame.contentDocument.querySelectorAll("div") it shows no option for replacing .last()

so my question is how can am i going write way?how to convert .last()

// something like this

let last = Array.from(document.querySelectorAll('div')).pop();