A prototype for quick filtering sidebar items in django admin

nav_sidebar.css

.sticky {
    position: sticky;
    top: 0;
    max-height: 100vh;
}

.toggle-nav-sidebar {
    z-index: 20;
    left: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 23px;
    width: 23px;
    border-right: 1px solid #eaeaea;
    background-color: #ffffff;
    cursor: pointer;
    font-size: 20px;
    color: #447e9b;
    padding: 0;
}

[dir="rtl"] .toggle-nav-sidebar {
    border-left: 1px solid #eaeaea;
    border-right: 0;
}

.toggle-nav-sidebar:hover,
.toggle-nav-sidebar:focus {
    background-color: #f6f6f6;
}

#nav-sidebar {
    z-index: 15;
    flex: 0 0 275px;
    left: -276px;
    margin-left: -276px;
    border-top: 1px solid transparent;
    border-right: 1px solid #eaeaea;
    background-color: #ffffff;
    overflow: auto;
}

[dir="rtl"] #nav-sidebar {
    border-left: 1px solid #eaeaea;
    border-right: 0;
    left: 0;
    margin-left: 0;
    right: -276px;
    margin-right: -276px;
}

.toggle-nav-sidebar::before {
    content: '\00BB';
}

.main.shifted .toggle-nav-sidebar::before {
    content: '\00AB';
}

.main.shifted > #nav-sidebar {
    left: 24px;
    margin-left: 0;
}

[dir="rtl"] .main.shifted > #nav-sidebar {
    left: 0;
    right: 24px;
    margin-right: 0;
}

#nav-sidebar .module th {
    width: 100%;
    overflow-wrap: anywhere;
}

#nav-sidebar .module th,
#nav-sidebar .module caption {
    padding-left: 16px;
}

#nav-sidebar .module td {
    white-space: nowrap;
}

[dir="rtl"] #nav-sidebar .module th,
[dir="rtl"] #nav-sidebar .module caption {
    padding-left: 8px;
    padding-right: 16px;
}

#nav-sidebar .current-app .section:link,
#nav-sidebar .current-app .section:visited {
    color: #ffc;
    font-weight: bold;
}

#nav-sidebar .current-model {
    background: #ffc;
}

.main > #nav-sidebar + .content {
    max-width: calc(100% - 23px);
}

.main.shifted > #nav-sidebar + .content {
    max-width: calc(100% - 299px);
}

@media (max-width: 767px) {
    #nav-sidebar, #toggle-nav-sidebar {
        display: none;
    }

    .main > #nav-sidebar + .content,
    .main.shifted > #nav-sidebar + .content {
        max-width: 100%;
    }
}

#nav-filter {
    width: 100%;
    box-sizing: border-box;
    padding: 5px 16px;
    margin: 5px 0;
    border: none;
    outline: none;
}

#nav-sidebar table {
    width: 100%;
}

nav_sidebar.html

{% load i18n %}
<button class="sticky toggle-nav-sidebar" id="toggle-nav-sidebar" aria-label="{% translate 'Toggle navigation' %}"></button>
<nav class="sticky" id="nav-sidebar">
  <input type="text" id="nav-filter" placeholder="Start typing a content name...">
  {% include 'admin/app_list.html' with app_list=available_apps show_changelinks=False %}
</nav>

nav_sidebar.js

'use strict';
{
    const toggleNavSidebar = document.getElementById('toggle-nav-sidebar');
    if (toggleNavSidebar !== null) {
        const navLinks = document.querySelectorAll('#nav-sidebar a');
        function disableNavLinkTabbing() {
            for (const navLink of navLinks) {
                navLink.tabIndex = -1;
            }
        }
        function enableNavLinkTabbing() {
            for (const navLink of navLinks) {
                navLink.tabIndex = 0;
            }
        }

        const main = document.getElementById('main');
        let navSidebarIsOpen = localStorage.getItem('django.admin.navSidebarIsOpen');
        if (navSidebarIsOpen === null) {
            navSidebarIsOpen = 'true';
        }
        if (navSidebarIsOpen === 'false') {
            disableNavLinkTabbing();
        }
        main.classList.toggle('shifted', navSidebarIsOpen === 'true');

        toggleNavSidebar.addEventListener('click', function() {
            if (navSidebarIsOpen === 'true') {
                navSidebarIsOpen = 'false';
                disableNavLinkTabbing();
            } else {
                navSidebarIsOpen = 'true';
                enableNavLinkTabbing();
            }
            localStorage.setItem('django.admin.navSidebarIsOpen', navSidebarIsOpen);
            main.classList.toggle('shifted');
        });
    }

    // init quick filter
    (function() {
        const options = [];
        const navSidebar = document.getElementById('nav-sidebar');
        if (!navSidebar) { return; }
        navSidebar.querySelectorAll('th[scope=row] a').forEach((container) => {
            options.push({title: container.innerHTML, node: container});
        });

        function checkValue(e) {
            let v = e.target.value;
            if (v) { v = v.toLowerCase(); }
            if (e.key === 'Escape') { v = ''; e.target.value = ''; } // clear input
            for (const o of options) {
                // show/hide parent <TR>
                o.node.parentNode.parentNode.style.display =
                    (!v || o.title.toLowerCase().indexOf(v) !== -1) ? '' : 'none';
            }
        }

        const nav = document.getElementById('nav-filter');
        nav.addEventListener('change', checkValue, false);
        nav.addEventListener('keyup', checkValue, false);
    })();
}