PredicateRule<T, E> class

A rule defined by a predicate function.

This is the simplest way to create a validation rule. The predicate returns true if the value is valid, false if it should produce error.

final positiveNumber = PredicateRule<int, String>(
  predicate: (value) => value > 0,
  error: 'Must be positive',
);
Inheritance
Available extensions

Constructors

PredicateRule({required bool predicate(T value), required E error})
Creates a rule from a predicate and error.
const

Properties

error → E
The error to return if the predicate returns false.
final
hashCode → int
The hash code for this object.
no setterinherited
predicate → bool Function(T value)
The predicate that determines validity. Returns true if the value is valid.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

andThen(Formix<T, E> next) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Chains this validator with next, running next only if this passes.
cached() → CachedFormix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Wraps this validator with single-value caching.
lazy() → LazyFormix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Creates a lazy validator that defers instantiation until first use.
lruCached({int maxSize = 10}) → LruCachedFormix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Wraps this validator with LRU (Least Recently Used) caching.
mapError<E2>(E2 mapper(E error)) → Formix<T, E2>

Available on Formix<T, E>, provided by the FormixExtensions extension

Maps errors from type E to type E2.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
optional({bool isEmpty(T value)?}) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Makes this validator optional - skips validation when empty.
recover(T onError(List<E> errors)) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Recovers from validation errors with a default value.
tap({void onValid(T value)?, void onInvalid(List<E> errors)?}) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Applies side effects without affecting validation.
toString() → String
A string representation of this object.
inherited
validate(T value) → ValidationResult<T, E>
Validates value and returns a ValidationResult.
override
when(bool condition(T value)) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Conditionally applies this validator based on condition.
whenNot(bool condition(T value)) → Formix<T, E>

Available on Formix<T, E>, provided by the FormixExtensions extension

Conditionally skips this validator based on condition.
withMessageFormatter(ErrorMessageFormatter<E> formatter) → Formix<T, String>

Available on Formix<T, E>, provided by the FormixExtensions extension

Maps errors to user-facing messages using formatter.

Operators

operator ==(Object other) → bool
The equality operator.
inherited