Debounce constructor

Debounce({ Duration delay = defaultDelay, bool leading = false, bool trailing = true, })

Debounce is used to control the frequency of function calls with support for flexible delay and "leading" / "trailing" options.

This class is especially useful when you need to prevent frequent repeated calls:

• when entering text (for example, search)
• when processing scroll events
• when using resize handlers
• when pressing buttons (for example, double-click protection)

Supports:

• delay — How long to wait after the last call before executing
• leading — If true, callback will be called on the first call before the interval expires.
• trailing — If true, callback will be called after the interval ends
• leading && trailing If both are true, leading callback will be called immediately before the interval expires and trailing callback will be called after the interval ends (if there were repeated calls)

Usage example:

final _debounce = Debounce(delay: Duration(seconds: 1), leading: false, trailing: true); ✅ Good!
Config: leading: false, trailing: true
Input:  1-2-3---4---5-6-|
Output: ------3---4-----6|

final _debounce = Debounce(delay: Duration(seconds: 1), leading: true, trailing: false); ✅ Good!
Config: leading: true, trailing: false
Input:  1-2-3---4---5-6-|
Output: 1-------4---5---|

final _debounce = Debounce(delay: Duration(seconds: 1), leading: true, trailing: true); ✅ Good!
Config: leading: true, trailing: true
Input:  1-2-3---4---5-6-|
Output: 1-----3-4---5---6|

final _debounce = Debounce(delay: Duration(seconds: 1), leading: false, trailing: false); ❌ Bad! Output empty!
Config: leading: false, trailing: false
Input:  1-2-3---4---5-6-|
Output: ----------------|

final _debounce = Debounce(delay: Duration(milliseconds: 500));

void onTextChanged(String text) {
  _debounce(() {
    // ...
  });
}

@override
void dispose() {
  _debounce.dispose();
  super.dispose();
}

Implementation

Debounce({this.delay = defaultDelay, this.leading = false, this.trailing = true})
    : assert(!delay.isNegative, '❌ [Bad] [Duration] delay must be positive!') {
  /*
   // We bind the finalizer to the [Debounce] object at the time of its creation.
   //
   // When the object is no longer in use (for example, it will be deleted by 'Garbage collectors'), the [_finalizer] will automatically call [dispose] for the [Debounce] object.
  _finalizer.attach(this, this, detach: this);
  */
}