LazyFormix<T, E> class

A validator that defers instantiation until first use.

The validator is only created when validate is called for the first time. Subsequent calls reuse the same instance.

final validator = Validate.lazy(() => Validate.all([
  StringRules.required(error: 'Required'),
  _buildExpensiveValidator(), // Only created on first validate()
]));

// Validator not yet created
validator.validate('test'); // Now created and cached
validator.validate('test2'); // Reuses same instance

This is useful for:

  • Validators with expensive setup/initialization
  • Conditional validators that may never be used
  • Breaking circular dependencies between validators
  • Reducing startup time by deferring validator construction
Inheritance
Available extensions

Constructors

LazyFormix(Formix<T, E> _factory())
Creates a lazy validator from a factory function.

Properties

hashCode → int
The hash code for this object.
no setterinherited
isInstantiated → bool
Returns true if the validator has been instantiated.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
validator → Formix<T, E>
Returns the underlying validator, creating it if necessary.
no setter

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.
materialize() → void
Forces instantiation of the underlying validator.
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.
reset() → void
Resets the lazy validator, allowing the factory to be called again.
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