lemonade 0.1.0

Simple, typesafe, object-oriented library for data validation

lemonade

Simple yet powerful library for data validation:

• Fully typesafe and null-safe API
• Universal for any standard data structures
• Written in pure dart
• 0 dependencies

Get started 🚀

First, add lemonade into pubspec.yaml file of your project:

dependencies:
  lemonade: ^0.1.0

... or with simple command:

dart pub add lemonade
# or for flutter project:
flutter pub add lemonade

Then import it into your dart file:

import 'package:lemonade/lemonade.dart';

And you are ready to go!

Usage

For example, you want to validate GeoJSON point object that looks like this:

{
    "type": "Point",
    "coordinates": [125.6, 10.1]
}

Validator for this schema will look like that:

final pointsValidator = Validator.object(
  items: {
    // "type": "Point"
    'type': Validator.equals('Point'),
    // "coordinates": [125.6, 10.1]
    'coordinates': Validator.list(
      item: Validator.number(),
      // Length exactly 2
      minItems: 2,
      maxItems: 2,
    ),
  },
);

Then you can check if any data looks like with very basic method:

final decodedData = jsonDecode('{"type":"Point","coordinates":[125.6,10.1]}');

print(pointsValidator.validate(decodedData)); // true

If you want to check, what exactly is wrong, you can use getError method:

final wrongData = jsonDecode('{"type":"Point","coordinates":[125.6,"10.1"]}');

print(pointsValidator.getError(wrongData)); // object.coordinates > list<number>[1] > expected(number).got(10.1)

String representation of the errors says that:

• In field "coordinates"
  • At index [1]
    • Expected any number
    • Got "10.1"

It's easy to decode and trace an error in your data, isn't it?