Feature Request: Add .toggle() extension for bool in Dart

[dbspoudel]

In Swift, the Bool type has a built-in .toggle() method that flips the value between true and false. It simplifies boolean state management and avoids repetitive expressions like:

isEnabled = !isEnabled;

I propose adding a .toggle() method for bool in Dart, which would allow:

bool isEnabled = false;
isEnabled.toggle();  // Now isEnabled is true
print(isEmabled) // true

Use Case
This feature would improve readability and reduce redundancy, especially in stateful applications where toggling booleans is common.

Proposed Implementation
A simple method can be added to bool class in the Dart SDK:

/// Toggles the value of this boolean and stores it back in the same variable.
///
/// Example:
/// ```dart
/// bool value = true;
/// value.toggle();
/// print(value); // false
/// ```
void toggle() {
    this = !this;
  }

Adding .toggle() to bool would improve developer experience, reduce verbosity, and align Dart with other modern programming languages.

References
Swift's toggle() method: here