Expands nested object references based on expand[] query parameters.

Stripe allows expanding related objects in responses. Instead of returning just an ID, the full object is returned.

Examples

# Without expansion
%Subscription{customer: "cus_123"}

# With expand[]=customer
%Subscription{customer: %Customer{id: "cus_123", email: "..."}}

# Nested expansion: expand[]=customer.default_source
%Subscription{
  customer: %Customer{
    id: "cus_123",
    default_source: %Card{id: "card_123", last4: "4242"}
  }
}

Usage

# In resource handlers
expand_params = parse_expand_params(conn.query_params)
hydrated = PaperTiger.Hydrator.hydrate(subscription, expand_params)