Exactly one
Transforms a collection into a single object only when its cardinality is exactly one.
Typed collection
Exactly one
Collection
Typed result
Vue d’ensemble
Transforms a collection into a single object only when its cardinality is exactly one.
Exemple
After filtering invoices by reference, require exactly one match before continuing with an irreversible operation.
Parameters 1
items
Typed collection supplied by a binding. The concrete element type is preserved or unified in outputs.
Outputs 1
item
Unique element of the collection, with its concrete type.
Behavior
The output preserves the concrete element type. An empty list or a list with multiple elements causes the node to fail.
Key point Collection operations preserve the data classification carried by their elements; filtering, sorting, or concatenating a list is not declassification.
Limits and responsibilities
- Use this node when uniqueness is a business guarantee, not simply to arbitrarily take the first element.
- Ambiguity is treated as an explicit process error.