FeatureReduceCallback<T> typedef

FeatureReduceCallback<T> = T? Function(T? previousValue, Feature<GeometryObject> currentFeature, int featureIndex)

Callback for featureReduce

The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

If an initialValue is provided to the reduce method:

• The previousValue argument is initialValue.
• The currentValue argument is the value of the first element present in the List.

If an initialValue is not provided:

• The previousValue argument is the value of the first element present in the List.
• The currentValue argument is the value of the second element present in the List.

FeatureReduceCallback previousValue is the accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied. currentFeature is the current Feature being processed. featureIndex is the current index of the Feature being processed.

Implementation

typedef FeatureReduceCallback<T> = T? Function(
  T? previousValue, // todo or Feature ?
  Feature currentFeature,
  int featureIndex,
);