Creates a value range for at most one value (0..1).
Allows zero or one value, resulting in an optional scalar type (undefined | V).
undefined | V
The value shape or union type
The value shape or union for the linked set
A range with no minimum count and maxCount=1
Creates a value range for at most one value (0..1).
Allows zero or one value, resulting in an optional scalar type (
undefined | V).