support datafields in projection

catalog/builder.go

@@ -115,6 +115,23 @@ func Apply(s Schema, source map[string]any) (Projection, error) {
 		truthy = DefaultTrueValues()
 	}
 
+	var attrs json.RawMessage
+	if len(s.AttributesFields) > 0 {
+		m := make(map[string]any)
+		for _, key := range s.AttributesFields {
+			if val, ok := source[key]; ok && val != nil {
+				m[key] = val
+			}
+		}
+		if len(m) > 0 {
+			b, err := json.Marshal(m)
+			if err != nil {
+				return Projection{}, fmt.Errorf("%w: marshal attributes: %w", ErrProjectionBuild, err)
+			}
+			attrs = b
+		}
+	}
+
 	p := Projection{
 		ItemID:           uint32Of(source, s.ItemIdField),
 		ID:               id,
@@ -122,6 +139,7 @@ func Apply(s Schema, source map[string]any) (Projection, error) {
 		Title:            stringOf(source, s.TitleField),
 		PriceIncVat:      price,
 		Currency:         cur,
+		Attributes:       attrs,
 		TaxClass:         tax,
 		InventoryTracked: boolOf(source, s.InventoryTrackedF, truthy),
 		DropShip:         boolOf(source, s.DropShipF, truthy),