https://gmhstudio.com/release/locke/production/v0.0.141/js/small.js

1(function (w, d) {
2    "use strict";
3
4    // do nothing unless media queries are supported, since we will be using
5    // `minimal.css` otherwise. Do nothing if support is lacking.
6    if (!Modernizr.mediaquery || !w.addEventListener) {
7        return;
8    }
9
10    // lookup common function's
11    var OPP = w.OPP;
12    var toggleClass = OPP.toggleClass;
13
14    // do nothing if common functions are not available
15    if (!toggleClass) {
16        return;
17    }
18
19    (function () {
20        // class used to indicate state of mobile menu
21        var menuActiveClass = 'is-mobile-nav-active';
22
23        // for repeated calls to `toggleClass()`
24        var docElem = d.documentElement;
25
26        // find required elements by `id`
27        var menuLink = d.getElementById('mobile-menu-link');
28        var header = d.getElementById('header');
29
30        function toggleMenu (e) {
31          if ( Modernizr.mq(OPP.smallMQ) ) {
32                toggleClass(docElem, menuActiveClass);
33                e.preventDefault();
34            }
35        }
36
37        // (de-)activate menu on click, when present
38        !!menuLink && menuLink.addEventListener('click', toggleMenu);
39        !!header && header.addEventListener('click', toggleMenu);
40    })();
41})(window, window.document);