Throttle class Null safety

Creates a throttled function that only invokes func at most once per every wait milliseconds. The throttled function comes with a Throttle.cancel method to cancel delayed func invocations and a Throttle.flush method to immediately invoke them. Provide leading and/or trailing to indicate whether func should be invoked on the leading and/or trailing edge of the wait timeout. The func is invoked with the last arguments provided to the throttled function. Subsequent calls to the throttled function return the result of the last func invocation.

Note: If leading and trailing options are true, func is invoked on the trailing edge of the timeout only if the throttled function is invoked more than once during the wait timeout.

If wait is Duration.zero and leading is false, func invocation is deferred until the next tick.

See David Corbacho's article for details over the differences between Throttle and Debounce.

Some examples:

Avoid excessively rebuilding UI progress while uploading data to server.

  void updateUI(Data data) {
    updateProgress(data);
  }

  final throttledUpdateUI = Throttle(
    updateUI,
    const Duration(milliseconds: 350),
  );

  void onUploadProgressChanged(progress) {
     throttledUpdateUI(progress);
  }

Cancel the trailing throttled invocation.

  void dispose() {
    throttled.cancel();
  }

Check for pending invocations.

  final status = throttled.isPending ? "Pending..." : "Ready";

Constructors

Throttle(Function func, Duration wait, {bool leading = true, bool trailing = true})
Creates a new instance of Throttle

Properties

hashCode int
The hash code for this object. [...]
read-only, inherited
isPending bool
True if there are functions remaining to get invoked.
read-only
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

call([List<Object>? args, Map<Symbol, Object>? namedArgs]) Object?
Dynamically call this Throttle with the specified arguments. [...]
cancel() → void
Cancels all the remaining delayed functions.
flush() Object?
Immediately invokes all the remaining delayed functions.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
inherited
toString() String
A string representation of this object. [...]
inherited

Operators

operator ==(Object other) bool
The equality operator. [...]
inherited