Uncaught ReferenceError on jQuery script-CodePudding

When I try to run this script

window.onpopstate = function(popEvent) {
    let urlPath = window.location.pathName;
    let slash = page.lastIndexOf("/");
    let page = urlPath.substr(slash 1);
    let $tab;

    if (page = '') {
        $tab = $("#tabs .tab:first-of-type");
        page = $tab.attr("href");
    }

    else { $tab = $("#tabs .tab[href=" CSS.escape(page) "]") }

    $tab.addClass("current").siblings().removeClass("current");

    $.ajax({url: "subpages/" page, function(html) {
        $(".append").html(html);
    } });
}

I’m getting the error message:

foo.js:38 Uncaught ReferenceError: Cannot access 'page' before initialization at window.onpopstate (foo.js:38:15)

I don’t really get what’s the problem.

Could someone help me out?

CodePudding user response：

This error was caused only by mistyping: page → urlPath

window.onpopstate = function(popEvent) {
    let urlPath = window.location.pathName;
    let slash = urlPath.lastIndexOf("/");  // HERE
    let page = urlPath.substr(slash 1);
    let $tab;

    if (page = '') {
        $tab = $("#tabs .tab:first-of-type");
        page = $tab.attr("href");
    }

    else { $tab = $("#tabs .tab[href=" CSS.escape(page) "]") }

    $tab.addClass("current").siblings().removeClass("current");

    $.ajax({url: "subpages/" page, function(html) {
        $(".append").html(html);
    } });
}