ResultFormat class abstract

Validation format for form step results.

Provides 35+ built-in validators via factory constructors, plus ResultFormat.compose for chaining multiple validators.

// Built-in validators
ResultFormat.email("Invalid email")
ResultFormat.range("Must be 1-10", 1, 10)
ResultFormat.pattern("Letters only", r'^[a-zA-Z]+$')

// Compose multiple validators
ResultFormat.compose([
  ResultFormat.minLength("Too short", 3),
  ResultFormat.maxLength("Too long", 50),
])
Implementers

Constructors

ResultFormat()
Public constructor for creating custom ResultFormat subclasses.
const
ResultFormat.age(String errorMsg)
Requires an integer between 0 and 150.
factory
ResultFormat.compose(List<ResultFormat> validators)
Applies validators in order and reports the first failure.
factory
ResultFormat.consent(String errorMsg)
Requires the consent checkbox to be ticked.
factory
ResultFormat.creditCard(String errorMsg)
Requires a 13-19 digit card number that passes the Luhn checksum.
factory
ResultFormat.custom(String errorMsg, bool validator(String))
Validates with your own predicate over the string form of the answer.
factory
ResultFormat.date(String errorMsg, String format)
Requires a DateTime. format is the pattern used when exporting it.
factory
ResultFormat.dateRange(String errorMsg, String format, {DateTime? minDate, DateTime? maxDate})
Requires a DateTime within minDate and maxDate, either of which may be null for an open bound.
factory
ResultFormat.email(String errorMsg)
Requires a syntactically valid email address.
factory
ResultFormat.expression(String expression)
Validates against the FormStack expression grammar. See ExpressionLanguage.
factory
ResultFormat.fileSize(String errorMsg, int maxBytes)
Requires a picked file no larger than maxBytes.
factory
ResultFormat.iban(String errorMsg)
Requires an IBAN that passes the mod-97 checksum.
factory
ResultFormat.length(String errorMsg, int count)
Requires a string of exactly count characters — PINs, fixed-width codes.
factory
ResultFormat.location(String errorMsg)
Requires a location to have been picked.
factory
ResultFormat.max(String errorMsg, num max)
Requires a number less than or equal to max.
factory
ResultFormat.maxLength(String errorMsg, int max)
Requires a string of at most max characters.
factory
ResultFormat.maxSelections(String errorMsg, int max)
Requires at most max options to be selected.
factory
ResultFormat.min(String errorMsg, num min)
Requires a number greater than or equal to min.
factory
ResultFormat.minLength(String errorMsg, int min)
Requires a string of at least min characters.
factory
ResultFormat.minSelections(String errorMsg, int min)
Requires at least min options to be selected.
factory
ResultFormat.multipleChoice(String errorMsg)
Requires at least one option to be selected.
factory
ResultFormat.name(String errorMsg)
Requires two or more characters, letters and spaces only.
factory
ResultFormat.none()
Accepts anything. Use for steps that collect data but impose no rule.
factory
ResultFormat.notBlank(String errorMsg)
Requires a string with at least one non-whitespace character.
factory
ResultFormat.notEmpty(String errorMsg)
Requires a non-empty String, Iterable or Map.
factory
ResultFormat.notNull(String errorMsg)
Requires any non-null value. The weakest "answer this" rule.
factory
ResultFormat.number(String errorMsg)
Requires a string of digits.
factory
ResultFormat.password(String errorMsg)
Requires 8+ characters with upper, lower, digit and symbol.
factory
ResultFormat.pattern(String errorMsg, String regex)
Requires the answer to match regex. The pattern is compiled once.
factory
ResultFormat.percentage(String errorMsg)
Requires a number between 0 and 100.
factory
ResultFormat.phone(String errorMsg)
Requires an E.164-shaped phone number, for example +14155552671.
factory
ResultFormat.range(String errorMsg, num min, num max)
Requires a number within min and max, both inclusive.
factory
ResultFormat.singleChoice(String errorMsg)
Requires exactly one option to be selected.
factory
ResultFormat.smile(String errorMsg)
Requires a satisfaction rating to have been chosen.
factory
ResultFormat.ssn(String errorMsg)
Requires a US Social Security Number, with or without dashes.
factory
ResultFormat.text(String errorMsg)
Requires a non-empty string.
factory
ResultFormat.url(String errorMsg)
Requires an http or https URL.
factory
ResultFormat.zipCode(String errorMsg)
Requires a US ZIP code, five digits or ZIP+4.
factory

Properties

code → String
Stable machine-readable identifier for this constraint.
no setter
hashCode → int
The hash code for this object.
no setterinherited
params → Map<String, Object?>
Constraint parameters surfaced on failure, for message interpolation.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

error() → String
Human-readable message shown when isValid returns false.
isValid(dynamic input) → bool
Whether input satisfies this constraint.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited
validate(dynamic input) → ValidationResult
Validates input, returning the reason for failure alongside the verdict.

Operators

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

Static Methods

fromJson(Object? spec) → ResultFormat?
Builds a validator from its JSON description.
register(String name, ResultFormatFactory factory) → void
Registers a named validator so "type": "<name>" can be used in JSON forms. See ValidatorRegistry.