nullx - dart nullability with confidence

nullx is a dart toolkit that enhances handling of nullable types, providing utilities for null-checking, navigating nullable structures, and robust error handling, for cleaner and more resilient code.

Features

• Provides utilities for null-checking
• Helps in navigating nullable structures
• Offers robust error handling

Getting started 🎉

To use this package, add nullx as a dependency in your pubspec.yaml file.

dependencies:
  nullx: ^latest_version

Here is a simple example of how to use nullx:

Collections

import 'package:nullx/nullx.dart';

void main() {
  final list = [1, null, 3, null];
  list.mapNonNull((item) => item * 2); // prints: [2, 6]
}

import 'package:nullx/nullx.dart';

void main() {
  final list = [1, null, 3, null];
  list.mapNonNullIndexed((item, index) => item * index); // prints: [0, 6]
}

import 'package:nullx/nullx.dart';

void main() {
  final List<int>? nullableList = [1, 2, 3];
  nullableList.whatIfNotNullOrEmpty(
    (list) => print(list), // whatIf
    () => print('List is null or empty'), // whatIfNot
  );
  // prints: [1, 2, 3]
}

import 'package:nullx/nullx.dart';

void main() {
  List<int>? nullableList = [1, 2, 3];
  print(nullableList.isNullOrEmpty); // prints: false

  nullableList = null;
  print(nullableList.isNullOrEmpty); // prints: true

  nullableList = [];
  print(nullableList.isNullOrEmpty); // prints: true
}

Types

import 'package:nullx/nullx.dart';

void main() {
  const String? nullableString = 'example';
  unwrapped(nullableString, (value) {});

  final List<String?> strings = [null, 'one', null, 'two', null];
  strings.map((s) => s.letNonNull((s) => s.length)).whereType<int>().toList();
}

import 'package:nullx/nullx.dart';

void main() {
    const int? nullableInt = 10;
    final resultInt = nullableInt.letNonNull((value) => value * 2); // prints: 2
}

import 'package:nullx/nullx.dart';

void main() {
  const int userAge = 20;
  executeIf(
    () => userAge >= 18,
    onConditionMet: () {
      // prints 'You are an adult.'
    },
    onConditionNotMet: () {
      // prints 'You are not an adult.'
    },
  );
}

import 'package:nullx/nullx.dart';

void main() {
  var userAge = 20;
  final result = executeIfAs<String>(
    () => userAge >= 18,
    onConditionMet: () => 'You are an adult.',
    onConditionNotMet: () => 'You are not an adult.',
  );
}

import 'package:nullx/nullx.dart';

void main() {
    void printValue(String value) {
      // prints 'The value is: $value'
    }

    notEmpty(nullableString, printValue);
}

import 'package:nullx/nullx.dart';

void main() {
    const String? nullableString = 'example';
    unwrapped(nullableString, (value) {}); // prints: 'example'
}

import 'package:nullx/nullx.dart';

void main() {
    var nullableString = 'Hello';
    nullableString.notEmpty((item) => print(item)); // prints: Hello
}

import 'package:nullx/nullx.dart';

void main() {
  const int userAge = 20;
  // Unwraps the nullable string and performs an operation on it
  callWhen(
    condition: () => userAge >= 18,
    onMet: () {
      // prints 'You are an adult.'
    },
    onNotMet: () {
      // prints 'You are not an adult.'
    },
  );
}

import 'package:nullx/nullx.dart';

void main() {
    const int? nullableInt = null;
    nullableInt.orZero; // Outputs: 0
    nullableInt.or(defaultValue: 5); // Outputs: 5

    const double? nullableDouble = null;
    nullableDouble.orZero; // Outputs: 0.0
    nullableDouble.or(defaultValue: 5.5); // Outputs: 5.5

    const bool? nullableBool = null;
    nullableBool.orFalse; // Outputs: false
    nullableBool.or(defaultValue: true); // Outputs: true
}

void main() {
    final Map<String, int>? nullableMap = {'a': 1, 'b': 2};
    print(nullableMap.isNullOrEmpty); // false
    print(nullableMap.getOrElse('c', 0)); // 0
    nullableMap.putIfAbsentOrElse('c', 3); // {a: 1, b: 2, c: 3}
    nullableMap.updateValue('a', (value) => value! + 10); // {a: 11, b: 2, c: 3}
    final filteredMap = nullableMap.filter((entry) => entry.value > 2);
    print(filteredMap); // {a: 11, c: 3}
}

Contributing

Contributions are welcome! Please read the contributing guide to learn how to contribute to the project and set up a development environment.

License

Copyright 2024 Oleksii Shtanko

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.