I am creating a checkout ui extension that take cart subtotal and show a message. I am able to get the cart total using useTotalAmount. But, there is no way to get the subtotal.
If anybody know how to get subtotal in checkout ui extension using the documentation https://shopify.dev/docs/apps/checkout/custom
Did you ever find a solution? I am running into the same issue. Strange that there isn’t a breakdown of all cart costs (subtotal, shipping, tax, etc) available in the cost object referenced here: https://shopify.dev/docs/api/checkout-ui-extensions/unstable/apis/standardapi
To get the subtotal, we looped through the lineitems and added the line amounts.
https://shopify.dev/docs/api/checkout-ui-extensions/unstable/react-hooks/cart/usecartlines