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A variable that can be subscribed to so the subscribers get notified when changes occur.


Create a NanoVar instance with a given initial value:

final counter = NanoVar(0);

Subscribe to changes made to the value of the NanoVar instance:

final unsubscribe = counter.subscribe((oldValue, newValue) {
    print("The counter changed from $oldValue to $newValue");

Assign a new value to the NanoVar instance:

counter.value = 1;

The callback declared above is now called with the assigned value and the previous value.

Call unsubscribe to make the NanoVar instance stop calling the callback:



This library was created to be used in Flutter NanoVar, which provides a lightweight method of state management in Flutter. However, NanoVar can be used on its own as well.