Youtube subscription search

// ==UserScript==
// @name           Youtube subscription search
// @namespace      https://www.youtube.com/
// @include        https://www.youtube.com/*
// @grant          GM_addStyle
// @require http://code.jquery.com/jquery-latest.js
// ==/UserScript==

GM_addStyle(`
#subSearch {
width: 100%;
padding: 6px 10px;
font-size: 16px;
color: #666;
background: #fff;
cursor:pointer;
}
#subSearch:hover {
background: #dcdcdc;
}
input#subSearch:focus {
  background-color: yellow;
}
ytd-guide-collapsible-entry-renderer[can-show-more],
#expander-item,
#collapser-item {
background-color: #e1e1e1 !important;
}
`);

$(function(){
    let sub_titles;
    let more_titles;

    let $sub_block = $('#sections').find('ytd-guide-section-renderer').eq(2);
    $sub_block.prepend(
        `
<input id="subSearch" type="text" placeholder="Find subscription"/>
`
    );

    sub_titles = $sub_block.find('#items').children('ytd-guide-entry-renderer').find('.title').toArray();

    $sub_block.on('keyup clear', '#subSearch', filterSubscriptions);
    $sub_block.on('click', 'ytd-guide-collapsible-entry-renderer', clearFilter);

    function filterSubscriptions(e) {
        const search_text = e.target.value.toLowerCase();

        sub_titles.forEach(function(subscription) {
            const item = subscription.textContent;
            if( item.toLowerCase().indexOf(search_text) != -1 ) {
                $(subscription).closest('ytd-guide-entry-renderer').css('display','block');
            } else {
                $(subscription).closest('ytd-guide-entry-renderer').css('display','none');
            }
        });
    }

    function clearFilter() {
        let checkExist = setInterval(function() {
            let attr = $sub_block.find('#items').children('ytd-guide-collapsible-entry-renderer').attr('expanded');

            if ( typeof attr !== undefined && attr !== false ) {
                $('#subSearch').val('').focus();
                $( "#subSearch" ).trigger( "clear" );

                more_titles = $sub_block.find('#items #expandable-items').children('ytd-guide-entry-renderer').find('.title').toArray();
                if(sub_titles.length < more_titles.length) {
                    sub_titles.push.apply(sub_titles, more_titles);
                }

                clearInterval(checkExist);
            }
        }, 100);

    }

});