未捕获的类型错误：无法读取未定义的开发工具控制台的属性“top”

Question

I have code like this

function (t, e, i, o) {
    "use strict";
    var s = t(".main-menu-wrap"), n = s.outerHeight() - s.outerHeight(), r = t(".header").next(".page-section"),
         a = r.position(), l = t(e).scrollTop();
    l >= a.top - n && s.addClass("fixedMenu"), t(e).scroll(function () {
        var i = t(e).scrollTop();
        i >= a.top - n ? s.addClass("fixedMenu") : s.removeClass("fixedMenu")
    }), t(".main-menu").singlePageNav({
        offset: t(".main-menu-bottom").outerHeight(),
        filter: ":not(.external)",
        updateHash: !0
    }), t(".manyItemsSlider").slick({
        infinite: !0,
        swipe: !0,
        slidesToShow: 5,
        slidesToScroll: 1,
        responsive: [{breakpoint: 992, settings: {slidesToShow: 3, slidesToScroll: 1}}, {
            breakpoint: 768,
            settings: {slidesToShow: 1, slidesToScroll: 1}
        }]
    }), t(".messagesSlider").slick({
        infinite: !0,
        swipe: !0,
        slidesToShow: 1,
        dots: !0,
        autoplay: !0,
        fade: !0,
        arrows: !1,
        slidesToScroll: 1
    }), t(".userFeedbackSlider").slick({
        infinite: !0,
        swipe: !0,
        slidesToShow: 2,
        dots: !0,
        autoplay: !0,
        fade: !1,
        arrows: !1,
        slidesToScroll: 1,
        responsive: [{breakpoint: 1200, settings: {slidesToShow: 1, slidesToScroll: 1}}]
    });
    var d = t(".toTop");
    d.length && d.on("click", function (e) {
        e.preventDefault(), t("html, body").animate({scrollTop: 0}, "slow")
    });
    var c = t(".scrollDown");
    c.length && c.on("click", function (i) {
        i.preventDefault();
        var o = t(e).height();
        t({myScrollTop: e.pageYOffset}).animate({myScrollTop: o}, {
            duration: 600, step: function (t) {
                e.scrollTo(0, t)
            }
        })
    })
}(jQuery, window, document);

In javascript console in dev tools In Chrome I have error: Uncaught TypeError: Cannot read property 'top' of undefined at main.js:1403 at main.js:1453.

1403 is l >= a.top - n && s.addClass("fixedMenu"), t(e).scroll(function () { and 1453 is }(jQuery, window, document);

But in Firefox I have the following error: Uncaught TypeError: a is undefined js/main.js:1403 js/main.js:1453

How can I fix this?

Answer 1

Issue seems with a not being defined on function evaluation which stems from the fact that r wasn't defined in the line above, the cause for which could be header not present in the t supplied. So, in a nutshell, check the first parameter being passed to this function