Template.flexboxLayout.events({ 'transitionend .sidebarMenu'(event) { if (!event.target.classList.contains('sidebarMenu')) { return; } handleResize(); } }); Template.flexboxLayout.helpers({ leftSidebarOpen() { return Template.instance().data.state.get('leftSidebar'); }, lesionSidebarOpen() { return Template.instance().data.state.get('rightSidebar') === 'lesions'; }, additionalFindingsSidebarOpen() { return Template.instance().data.state.get('rightSidebar') === 'additional'; }, rightSidebarOpen() { return Template.instance().data.state.get('rightSidebar') !== null; } });