Side Cart exposes two filters for theme and plugin authors. There are no do_action hooks — only the two filters below.
side_cart_trigger_selectors
Tells Side Cart which existing element(s) on the page should open the drawer, when the trigger mode is set to use your theme’s own cart icon instead of Side Cart’s built-in one.
add_filter( 'side_cart_trigger_selectors', function ( $selectors ) {
$selectors[] = '.my-theme-cart-icon';
return $selectors;
} );The default selectors are .cart-contents and any link pointing at the cart page.