Auto add product in cart page

In Shopify, automating the addition of products to the cart page streamlines the purchasing process for customers. This functionality enables the automatic inclusion of specific products into the cart when users visit the cart page, eliminating the need for manual selection. Merchants can implement this feature through various methods such as using JavaScript, Liquid code, or third-party apps. By simplifying the checkout process, auto-adding products in the cart page can enhance user experience and potentially boost sales on the Shopify platform.

{% assign product = all_products['make-it-a-gift'] %}

{% unless cart.item_count == 0 or product.empty? or product.variants.first.available == false %}

{% assign variant_id = product.variants.first.id %}

<script>
(function($) {

var cartItems = {{ cart.items | json }},
qtyInTheCart = 0,
cartUpdates = {};

for (var i=0; i<cartItems.length; i++) {
if ( cartItems[i].id === {{ variant_id }} ) {
qtyInTheCart = cartItems[i].quantity;
break;
}
}

if ( ( cartItems.length === 1 ) && ( qtyInTheCart > 0 ) ) {
cartUpdates = { {{ variant_id }}: 0 }
}
else if ( ( cartItems.length >= 1 ) && ( qtyInTheCart !== 1 ) ) {
cartUpdates = { {{ variant_id }}: 1 }
}
else {
return;
}

var params = {
type: 'POST',
url: '/cart/update.js',
data: { updates: cartUpdates },
dataType: 'json',
success: function(stuff) {
window.location.href = '/cart';
}
};

$.ajax(params);

})(jQuery);
</script>

{% endunless %}

{% assign product = all_products['make-it-a-gift'] %}
  {% assign variant_id = product.variants.first.id %}