Must be
Yes, you are not wrong, this is another validation package.
However more much idiomatic, for example, validate value using cascade syntax.
It's similar to a framework that checks values in tests.
requireThat('value')..mustBeGreaterThan(6)..mustBeLessThanOrEqualTo(10)
Set constraints in your data
Validation of a value.
requireThat('teste@gmail.com').mustBeEmail()
You can set what is the validation field name.
requireThat('teste@gmail.com', name: 'email').mustBeEmail()
But, what happens when the date violates the restriction?
An exception
is thrown with the violate constraint with a message containing the data and field name if have.
requireThat('teste@gmail.com').mustBeEmail('error')
But if I want to define more constraints?
That Dart side is with us, so let's use the cascade operator syntax.
requireThat('value')..mustBeGreaterThan(6)..mustBeLessThanOrEqualTo(10)
That's amazing.
Create your constraint
Here again Dart side will help us with the extension methods
extension_dart.
Firstly, create a Constraint
subclass, e.g:
class SameDay extends Constraint {
const SameDay(this.date, [String? message]) : super(message);
final DateTime date;
}
Now, create an extension of the Require
with the generic of the data type that to want to validate, call the method how you want, (the pattern is mustBe...
), and inside it calls the
mustBe` method.
extension RequireString<T extends String> on Require<T?> {
/// Verifies if the [String] is blank.
void mustBeBlank([String? message]) =>
mustBe(value?.trimLeft().isEmpty ?? true, Blank(message));
}
In Require
you can access the value and the field name(value and name).
How validate?
When a restriction is violated an exception
is thrown, then there is a support function that captures this and returns its message, if there is no violation then returns null
.
validate(
() => requireThat(10).mustBeGreaterThan(10),
ifNotValid: (_) => 'error',
) // print -> 'error'
You can also do whatever you want with each restriction that is violated.
validate(
() => requireThat(10)..mustBeGreaterThan(10)..mustBeLessThan(100),
ifNotValid: (constraint) => constraint.when({
isType<LessThan>(): (_) => 'less',
isType<GreaterThan>(): (_) => 'greater',
}),
)
You can use try/catch
too.
For the customize you message see below Custom error message.
It's perfect to use in the TextFormFields
validation.
TextFormField(
validator: (value) => validate(
() => requireThat(value, name: 'nick')
..mustBeGreaterThanOrEqualTo(3)
..mustBeLessThan(10),
),
decoration: const InputDecoration(
labelText: 'Nickname',
border: OutlineInputBorder(),
),
),
Custom error message
If you want to change the constraint default message when calling the validate
function, use the ValidationsLocalization
.
void main() {
ValidationsLocalization.on<Email>((constraint) => 'custom message - ${constraintException.name}-${constraintException.value}');
}
This does not translate or change the constraint exception message, for this do:
requireThat('value').mustBeGreaterThan(5, 'custom message');
In the validate
function there is ifNotValid
function then pass the message do you want according to the constraint violated.
validate
() => requireThat(10).mustBeGreaterThan(0),
ifNotValid: (constraint) => constraint.when({
isType<LessThan>(): (_) => 'less',
isType<GreaterThan>(): (_) => 'greater',
}),
)
Tests
There is a new matcher
for the throwing ConstraintException
:
expect(
() => requireThat(2, name: 'number').mustBeGreaterThan(2),
throwsConstraintException<GreaterThan>(
constraintMessage: 'Must be greater than 2',
name: 'number',
value: 2,
),
);
📝 Maintainers
🤝 Support
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📝 License
Copyright © 2023 Kauê Martins.
This project is MIT licensed.