cant not bundle without issues

[Seabizkit]

This can not bundle,

$(function () {
    ParadoxPanelResizer.attachPanel("split-panel", "split-left");
});

var ParadoxPanelResizer = {

    attachPanel: function (panelId, targetId) {

       // debugger;

        const BORDER_SIZE = 4;
        const panel = document.getElementById(panelId);
        if (panel == null)
            return;
        const target = document.getElementById(targetId);
        let m_pos;

        function resize(e) {
            //console.log("resizing");
            const dx = m_pos - e.x;
            m_pos = e.x;
            target.style.width = (parseInt(getComputedStyle(target, '').width) - dx) + "px";
        }

        //function mousemoveRemove(e) {
        //    console.log("remove-mousemove");
        //    resize(e);
        //}

        panel.addEventListener("mousedown", function (e) {

           // console.log("add-mousedown");
            //if (e.offsetX < BORDER_SIZE) {
                m_pos = e.x;
                document.addEventListener("mousemove", resize, false);
          //  }
        }, false);

        document.addEventListener("mouseup", function () {
            //console.log("add-mouseup");
            document.removeEventListener("mousemove", resize, false);
        }, false);
    }

};