Navigating Customer Existence in Shopify Functions for Cart Transformations

[sajjadmurtaza]

When working with a Shopify function for cart transformation, ensuring customer existence before payment can be crucial.
There are instances where the customer might appear as null until after the payment, as the creation of the customer might occur during or after checkout.
How can one handle situations where the customer might not be available during function creation, despite being present after the payment?

query Input {
  cart {
    buyerIdentity {
      customer {
        id
        hasAnyTag(tags: ["prime"])
      }
    }
    lines {
      quantity
      cost {
        amountPerQuantity {
          amount
        }
      }
      merchandise {
        __typename
        ...on ProductVariant {
          id
          product {
            hasAnyTag(tags: ["prime"])
          }
        }
      }
    }
  }
  
}