primitives library

Contains fundamental primitives and change notification types used throughout the extensions package.

This library provides isolated types that are shared across multiple components, inspired by Microsoft.Extensions.Primitives.

Change Tokens

Track and react to changes in data sources:

// Create a change token source
final cts = CancellationTokenSource();
final changeToken = CancellationChangeToken(cts.token);

// Register a callback
changeToken.registerChangeCallback(() {
  print('Data changed!');
});

// Signal change
cts.cancel();

Change Token Patterns

Use utility methods for common patterns:

// React to changes with state
ChangeToken.onChangeTyped<MyData>(
  () => dataSource.getChangeToken(),
  (data) => print('New data: $data'),
);

// Composite change tokens
final token = CompositeChangeToken([token1, token2, token3]);
// Fires when any constituent token changes

Validation

Use validation results for options validation:

ValidationResult.success();
ValidationResult.fail('Invalid value');