MapSignal

A reactive Signal that holds a Map and implements the Map interface.

MapSignal lets you listen to changes on a map reactively and mutate it directly using standard map operations (like adding/modifying keys with operator []=, addAll, remove, clear, etc.). Any mutations automatically trigger reactive updates to all active listeners (e.g., inside an effect or computed).

Additionally, MapSignal defines convenient operators:

• << injects/adds all entries from another map into the current map.
• & forks/concatenates the map with another map into a new MapSignal.
• | pipes/concatenates the map with another signal holding a map into a new MapSignal.

Example Usage#

import 'package:signals/signals.dart';

void main() {
  final settings = mapSignal<String, dynamic>({
    'theme': 'light',
    'notifications': true,
  });

  effect(() {
    print('Theme is currently: ${settings['theme']}');
  }); // Prints: "Theme is currently: light"

  // Update key/value pair directly (triggers updates)
  settings['theme'] = 'dark'; // Prints: "Theme is currently: dark"

  // Expose standard Map methods
  settings.remove('notifications');
}

Constructors#

Methods#

mapSignal#

Creates a MapSignal initialized with the provided map.

This is a convenience helper function for creating reactive map signals.

import 'package:signals/signals.dart';

final settings = mapSignal({'theme': 'dark'});