Assigning to rvalue

Bugs
1

Hello I have a problem with my js code.

addScrollListener = (id, totalSize) => {
    // logger.debug(id+' scroll on bottom');
    // logger.debug('totalSize: ' + totalSize);
    let lastScrollTop;
    let fn = window['fn_' + id];
    $('#' + id).scroll(function(e) {
        let elemsSize = $(this).find('.v-csslayout').length; //

        // logger.debug('filter scrolled');
        let scrollTop = $(this).scrollTop(),
            innerHeight = $(this).innerHeight(),
            scroll_height = $(this)[0].scrollHeight;
        // fn('scrollTop: '+scrollTop+', innerHeight:'+innerHeight+', scroll_height: '+scroll_height);

        if (scrollTop + innerHeight >= scroll_height && lastScrollTop != scrollTop) {
            fn(true);
            lastScrollTop = scrollTop;
        }
    });
}

id parameter has a error “Parsing Errror: Assigning to rvalue”

2

If you stated what level this was from you might get some responses. Thanks.