reactive_data_set #

A simple yet powerful in-memory data manager for Flutter, inspired by Delphi's TDataSet.

ReactiveDataSet<T> provides a reactive, mutable, and easily sortable/filterable list structure that integrates seamlessly with native Flutter widgets like ValueListenableBuilder. It’s built to support common data manipulation use-cases in a clean and reusable way.

✨ Features #

• ✅ Generic, type-safe data holder (ReactiveDataSet<T>)
• 🔄 Reactive UI updates using ValueNotifier<List<T>>
• 🧹 Non-destructive filtering and sorting
• ➕ Insert, ✏️ update, ❌ delete, 🔁 reset, 🧽 clear operations
• � Safe data querying with getByIndex, getWhere, and getFirstWhere
• �🔒 Maintains original data intact while presenting filtered/sorted views
• 🧩 Native Flutter-only (no external state management required)

🧠 Delphi TDataSet Inspiration #

This package takes inspiration from Delphi's classic TDataSet component.

💡 Unlike TDataSet, which was database-bound, ReactiveDataSet is purely in-memory and UI-friendly, perfect for modern reactive UIs. It embraces the spirit of data-awareness while staying lightweight and native.

🚀 Getting Started #

1. Add the package #

flutter pub add reactive_data_set

2. Define your data model #

class Person {
  final String name;
  final int age;

  Person(this.name, this.age);
}

3. Create and use the data set #

final dataSet = ReactiveDataSet<Person>([
  Person('Alice', 30),
  Person('Bob', 25),
]);

4. Bind to the UI #

ValueListenableBuilder<List<Person>>(
  valueListenable: dataSet.dataListenable,
  builder: (context, people, _) {
    return ListView.builder(
      itemCount: people.length,
      itemBuilder: (_, index) => Text(people[index].name),
    );
  },
);

5. Query your data #

// Get item by index (null-safe)
Person? person = dataSet.getByIndex(0);
if (person != null) {
  print('First person: ${person.name}');
}

// Get all items matching a condition
List<Person> adults = dataSet.getWhere((p) => p.age >= 18);
print('Found ${adults.length} adults');

// Get first item matching a condition
Person? youngest = dataSet.getFirstWhere((p) => p.age < 30);
if (youngest != null) {
  print('Youngest person under 30: ${youngest.name}');
}

⚙️ API Overview #

ReactiveDataSet<T>(
  [List<T>? initialData]
)

// Mutations
void insert(T item)
void delete(int index)
void update(int index, T updatedItem)

// Sorting & Filtering
void sort(Comparable Function(T) selector, {bool ascending = true})
void filter(bool Function(T) predicate)
void reset()
void clear()

// Data Access
List<T> get data
ValueNotifier<List<T>> get dataListenable
T? getByIndex(int index)
List<T> getWhere(bool Function(T) predicate)
T? getFirstWhere(bool Function(T) predicate)

🛣️ Roadmap (Future Ideas) #

• ⏪ Undo/Redo stack for revertible operations
• 📦 Batched updates/transactions
• 🔍 Pagination and search helpers
• 🔗 Nested dataset support (parent/child relationships)
• 🧾 JSON serialization helpers

🛠 Contributing #

Feel free to open issues or pull requests for bugs, improvements, or new features. The goal is to keep it simple, fast, and native.

Built with ❤️ by a former Delphi developer for modern Flutter apps.

📄 License #

MIT License. Use it freely in personal and commercial projects.