Lists and tuples

Lists

list(schema) parses every element with the same schema. schema.list() is equivalent.

final names = string().trim().min(2).list();
final List<String> parsed = names.parse([' Ada ', 'Grace']);
print(parsed); // [Ada, Grace]

Failed children include their integer index in the issue path. Unchanged typed lists can reuse their input; use List.of(parsed) for an independent outer list.

Length

list(string()).min(1);
list(string()).max(10);
list(string()).length(3);

Membership and uniqueness

list(string()).contains('admin');
list(string()).anyOf(['admin', 'editor']);
list(string()).everyOf(['admin', 'editor']);
list(string()).unique();

Check	Requirement
contains(value)	At least one element equals the value
anyOf(values)	At least one element belongs to the allowed values
everyOf(values)	Every element belongs to the allowed values
unique()	No two elements compare equal

Checks run on parsed elements and use Dart equality. everyOf() does not require every allowed value to appear. Container equality is not automatically structural.

unwrap()

final names = string().min(2).list();
final element = names.unwrap();
print(element.tryParse('A').isValid); // false

Tuples

tuple() assigns a schema to each position and requires the declared length. Output is a heterogeneous list.

final point = tuple([string(), number(), number()]);
print(point.parse(['home', 10, 20])); // [home, 10, 20]

.and() includes the receiver as the first element.

final pair = string().and([integer()]);
print(pair.parse(['Ada', 28])); // [Ada, 28]

variadic()

Repeat the final schema zero or more times after the fixed prefix. The minimum length is one less than the original tuple length.

final row = tuple([string(), number()]).variadic();
print(row.parse(['scores', 10, 20, 30])); // [scores, 10, 20, 30]
print(row.validate(['scores'])); // true

Nullable lists and elements

final List<String?> elements = string().nullable().list().parse(['Ada', null]);
final List<String>? collection = string().list().nullable().parse(null);

Modifier order determines which value can be null. See nullable values.