booking-calendar

Shows the slots of a bookable product (its Booking schedule, set in the Shopify admin) for days days, the places left of each, the day in the site's language and the time in the place's time zone; picking a free slot books it as its container says. In a booking-form: the form books it. In a product's add to cart: adding the product holds the slot for the quantity and writes it on the product's lines (a paid appointment); no slot or a full one stops the addition with the message, and an addition that does not get in (Shopify refuses it) gives the slot back. In the cart: the picked slot is written on the cart (a pickup or delivery window) and held only when the visitor checks out, so picking holds no place; a slot taken by someone else meanwhile stops the checkout, with the message in [booking="error"], and with data-required the checkout stops until a slot is picked. The places are counted by Smootify: two visitors cannot book the last one. The availability is kept a minute, so pages opened again ask nothing.