Sharepoint: Add an action button to go 'Up' one folder in the file browser

sharepoint-up-actionbtn.user.js

// ==UserScript==
// @name         Sharepoint: Go Up One Folder Action Button
// @namespace    https://github.com/niikoo
// @version      0.4.1
// @description  Add an action button to go 'Up' one folder in the file browser
// @author       niikoo
// @homepage     https://gist.github.com/niikoo/a49658ed816b35522831031f6a80992b
// @match        https://*.sharepoint.com/*
// @updateURL    https://gist.github.com/niikoo/a49658ed816b35522831031f6a80992b/raw/sharepoint-up-actionbtn.user.js
// @downloadURL  https://gist.github.com/niikoo/a49658ed816b35522831031f6a80992b/raw/sharepoint-up-actionbtn.user.js
// @supportURL   https://gist.github.com/niikoo/a49658ed816b35522831031f6a80992b
// @run-at       document-body
// @grant        none
// @noframes
// ==/UserScript==

/*
 * Changelog
 * -
 * 0.4.1 * Fix update & download URL
 * 0.4.0 * Fix so that it works on more sites
 * 0.3.0 * Auto updating; better metadata incl. script run-at.
 * 0.2.0 * Fix error message because of missing jQuery by waiting for it. Update metadata.
 * 0.1.0 * Initial build
 */

(function() {
    'use strict';

    function checkIfCustomButtonExists() {
        if(window.$("body").find("#UpOneLevelBtn_Custom").length != 0) return true; // Do not create multiple up buttons
        return false;
    }

    function setupCustomUpButton() {
        if(checkIfCustomButtonExists()) return;
        console.log('Try to add up button');
        var currentUrl = window.location.protocol + "//" + window.location.host + window.location.pathname;
        if(window.location.search == null) return;
        var queryParams = decodeURIComponent(window.location.search).substring(1).split('&');
        try {
            let pathnameArr = location.pathname.split('/SitePages');
            let rootFolderPath = '/';
            if(pathnameArr.length === 2) {
                rootFolderPath = pathnameArr[0];
            }
            var rootFolder = queryParams.filter(el => el.startsWith("RootFolder="))[0].substr(11).split('/');
            queryParams = queryParams.filter(el => !el.startsWith("RootFolder="));
            if(rootFolder.length == 0) {
                console.log('Not possible to go more up');
                return;
            }
            rootFolder.pop();
            var rootFolderOneUp = "RootFolder=" + rootFolder.join('/');
            queryParams.push(rootFolderOneUp);
            var newQueryParams = '?' + queryParams.join('&');
            var newOneUpUrl = currentUrl + newQueryParams;
            var $toolbar = window.$("div#t-container").find("div.ms-wpContentDivSpace[webpartid]").find("div.ms-listview-qcbContainer").find(".ms-qcb-root > ul:eq(0)");
            var $liUpOneLevel = window.$("<li class='ms-qcb-item' />");
            var $btnUpOneLevel = window.$("<button class='ms-qcb-button ms-qcb-buttons-alignmentfix js-listview-qcbUploadButton js-callout-body js-qcb-button ' type='button' title='Go Up One Level' id='UpOneLevelBtn_Custom' role='button' aria-expanded='false' accesskey='backspace' />");
            $btnUpOneLevel.click(function() {
                window.location.href = newOneUpUrl;
            });
            $btnUpOneLevel.text("Up");
            var $spanIconUpOneLevel = window.$("<span class='ms-qcb-glyph ms-listview-glyph-withmargin ms-core-form-heading' />");
            $spanIconUpOneLevel.html("&#xE047;");
            $btnUpOneLevel.prepend($spanIconUpOneLevel);
            $liUpOneLevel.append($btnUpOneLevel);
            if(checkIfCustomButtonExists()) return;
            $toolbar.prepend($liUpOneLevel);
        } catch (ex) {
            console.warn('Could not go up futher because of: ' + ex);
        }
    }

    let jQueryWaitFunction = function(waitRetries) {
        if (window.$ == null) {
            if(waitRetries < 0) {
                throw new Error("jQuery never appeared...");
            }
            setTimeout(jQueryWaitFunction(--waitRetries), 100);
        } else {
            window.$(function() {
                setupCustomUpButton();
            });
            return;
        }
    }

    jQueryWaitFunction(30); // Run on page load
})();