Add sorting to jira backlog view

jira-sorting.js

(() => {
const issueBlocks = $('.js-issue-list');
$(issueBlocks).map(function() {
    const issueBlock = this;

    let sortingRow = document.createElement('div');
    sortingRow.innerHTML = `<div class="ghx-issue-content">
      <div class="ghx-row">
        <span class="ghx-type" data-sort="ghx-type" data-key="title" title="Issue Type">
          IT
        </span>
        <div class="ghx-flags" style="vertical-align: initial">
          <span class="ghx-priority" data-sort="ghx-priority" data-key="title" title="Priority">
            P
          </span>
        </div>
        <div class="ghx-key" data-sort="ghx-key" title="Ticket #">
            Ticket #   &nbsp;
        </div>
        <div class="ghx-summary">
          <span class="ghx-inner" data-sort="ghx-summary">Title</span>
        </div>
      </div>
      <div class="ghx-end ghx-row">
        <span class="ghx-end">
          <span data-sort="aui-label.ghx-label" data-key="data-epickey">Epic &nbsp;&nbsp;&nbsp;</span>
          <span data-sort="ghx-avatar-img" data-key="alt">A &nbsp;&nbsp;</span>
          <span data-sort="ghx-statistic-badge" >SP</span>
        </span>
      </div>
    </div>`;
    sortingRow.classList ='sorting js-issue ghx-issue-compact';
    issueBlock.prepend(sortingRow);

    $(sortingRow).find('[data-sort]').on('click', function(event) {
        event.target.attributes['data-order'] = event.target.attributes['data-order'] || { value: 1};
        const sortBy = event.target.attributes['data-sort'].value;
        const invert = event.target.attributes['data-order'].value || -1; 
        const key = event.target.attributes['data-key'] ? event.target.attributes['data-key'].value : null;
        event.target.attributes['data-order'].value *= -1;

        issueBlock;
        const children = $(issueBlock).children('.js-issue:not(.sorting)');

        children.sort(function(a,b) {
            const first = $(invert === 1 ? a : b).find(`.${sortBy}`);
            const second = $(invert === 1 ? b : a).find(`.${sortBy}`);
    
            if (key) {
                return (first.attr(key) || '').localeCompare((second.attr(key) || ''));
            }

            return first.text().localeCompare(second.text());
        });

        children.map(function(c) {
            issueBlock.appendChild(this);
        });

    })
});
})();