Make WooCommerce block checkout coupon field open by default

Add this PHP code to your child themes functions file or custom code snippets plugin to make the coupon field open on page load by default.

By default, it’s closed.

add_action( 'wp_enqueue_scripts', 'bd_keep_coupon_field_open_inline', 20 );
function bd_keep_coupon_field_open_inline() {
    if ( is_checkout() ) {
        wp_register_script( 'bd-checkout-inline', '', [], '', true );
        wp_enqueue_script( 'bd-checkout-inline' );

        wp_add_inline_script( 'bd-checkout-inline', "
            jQuery(document).ready(function($) {
                const observer = new MutationObserver(function() {
                    const \$couponButton = $('.wc-block-components-panel__button');
                    if (\$couponButton.length && \$couponButton.attr('aria-expanded') === 'false') {
                        \$couponButton.trigger('click');
                        observer.disconnect();
                    }
                });

                observer.observe(document.body, {
                    childList: true,
                    subtree: true
                });
            });
        " );
    }
}

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