form_warden

Description:

form warden

form_warden #
A very simple package to help you write robust, reusable and extendable validations to go with your Flutter Forms.

How it works #
Building Blocks #
Create simple or complex blocks of validation, and compose those building blocks to create flutter validators.
Each block will have it's own logic, a set of args to create dynamic validators & specific error messages for each block.

There are simple ones, configurable ones and even you can create validations aligned to the domain of the app.

Creating a warden #
A warden will be a collection of validation blocks. Examples of enum & email pattern checking is added below.


Installation #
To use this package, add form_warden as a dependency in your pubspec.yaml file.
Usage #
Import the package
import 'package:form_warden/form_warden.dart';
copied to clipboard
Required field (inbuilt-validator)
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: createWarden([Validators.required]),
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: f.label,
),
onSaved: null,
),

copied to clipboard
Required email field (using inbuilt validator)
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: createWarden([Validators.required, Validators.email]),
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: f.label,
),
onSaved: null,
),
copied to clipboard
Custom validator
ValidatorFunction greaterThanTen = (value) {
if (value is int && value > 10) {
return null;
}
return "Must be greater than 10";
};
copied to clipboard
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: createWarden([greaterThanTen]),
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: f.label,
),
onSaved: null,
)
copied to clipboard
Club multiple validators together to create robust validators
ValidatorFunction greaterThanTen = (value) {
if (value is int && value > 10) {
return null;
}
return "Must be greater than 10";
};
ValidatorFunction lessThanHundred = (value) {
if (value is int && value < 100) {
return null;
}
return "Must be less than 100";
};
copied to clipboard

TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: createWarden([greaterThanTen, lessThanHundred]),
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: f.label,
),
onSaved: null,
)
copied to clipboard
Using higher order functions create configurable validators
ValidatorFunction between(int lowerLimit, int upperLimit) {
ValidatorFunction greaterThanLowerLimit = (dynamic? value) {
if (value.isEmpty) return null;
var _v = int.parse(value);
if (_v > lowerLimit && _v < upperLimit) return null;
return "Value must be between $lowerLimit and $upperLimit";
};
return greaterThanLowerLimit;
}
copied to clipboard
TextFormField(
autovalidateMode: AutovalidateMode.onUserInteraction,
validator: createWarden([between(10, 100)]),
decoration: InputDecoration(
border: OutlineInputBorder(),
labelText: f.label,
),
onSaved: null,
)

copied to clipboard
License #
MIT