SmartDebouncer class

A smart debouncer that dynamically adjusts its delay based on the user's actual typing speed using the Exponential Moving Average (EMA) algorithm.

Unlike a traditional debouncer with a fixed delay, SmartDebouncer continuously learns the user's typing rhythm and adapts accordingly:

  • Fast typers get a shorter debounce delay for snappy responsiveness.
  • Slow typers get a longer delay to avoid premature API calls.

Algorithm

  1. EMA Update: On each keystroke, the interval between keystrokes is smoothed via EMA:

    currentEma = (interval * alpha) + (currentEma * (1 - alpha))

  2. Dynamic Delay: The actual debounce delay is calculated as:

    dynamicDelay = currentEma * multiplier

  3. Safety Clamp: The delay is clamped between minDelay and maxDelay.

  4. Pause Filtering: If the interval exceeds pauseThreshold, it's treated as a natural pause (not typing), and the EMA is not updated.

Usage

final debouncer = SmartDebouncer();

TextField(
  onChanged: (value) {
    debouncer.run(() {
      // Call your search API here
      searchApi(value);
    });
  },
);

// Don't forget to dispose!
@override
void dispose() {
  debouncer.dispose();
  super.dispose();
}

Constructors

SmartDebouncer({int minDelay = 150, int maxDelay = 800, double alpha = 0.3, int pauseThreshold = 1500, double multiplier = 1.5})
Creates a SmartDebouncer with configurable parameters.

Properties

alpha → double
EMA smoothing factor (0.0–1.0).
final
currentDelay → int
Returns the current calculated dynamic delay in milliseconds, clamped between minDelay and maxDelay.
no setter
currentEma → double
Returns the current EMA value (for debugging/testing purposes).
no setter
hashCode → int
The hash code for this object.
no setterinherited
maxDelay → int
Maximum debounce delay in milliseconds.
final
minDelay → int
Minimum debounce delay in milliseconds.
final
multiplier → double
Multiplier applied to the EMA to compute the debounce delay.
final
pauseThreshold → int
Threshold in milliseconds to detect natural pauses.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

dispose() → void
Cancels the current timer to prevent memory leaks.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reset() → void
Resets the EMA back to its initial value and clears the last call time.
run(void action()) → void
Executes action after a dynamically calculated debounce delay.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited