type constraint. When set, Errand validates the value at run time and converts it to the declared type automatically.
Primitive types
Collection types
list
An ordered collection of values of the same type:set
An unordered collection with unique values:map
A collection of key-value pairs where all values share the same type:object
A collection of named attributes with potentially different types:tuple
An ordered list where each position has a fixed type:Optional attributes
Useoptional(type) or optional(type, default) within an object to mark fields as optional:
optional(type, default) use the given default when not provided. Fields declared with optional(type) default to null.
Omitting the type
Without atype, Errand accepts any value without validation:
type, it is always treated as a string.