[Nexus]

<div id="cart" style="display:none">block</div>
<button type="button" id="button">Toggle</button>
<script>
try {
    const cart = document.getElementById('cart');
    const button = document.getElementById('button');

    button.addEventListener('click', function() {
        const isHidden = +(cart.style.display === 'none');
        cart.style.display = ['none', 'block'][isHidden];
        localStorage.setItem('cart-expanded', isHidden);
    });

    if (+localStorage.getItem('cart-expanded'))
        button.click();

} catch (e) {
    console.error(e);
};
</script>