create1

ResettableSelector<S, R> create1<S, T1, R>(

  1. Selector<S, T1> selector1,

  2. R combiner(
    1. T1
    )
)

Creates a resettable selector with one input.

Implementation

static ResettableSelector<S, R> create1<S, T1, R>(
  Selector<S, T1> selector1,
  R Function(T1) combiner,
) {
  T1? lastInput;
  R? lastResult;
  var hasCache = false;

void reset() {
lastInput = null;
lastResult = null;
hasCache = false;
}


R select(S state) {
final input = selector1(state);


if (hasCache && identical(input, lastInput)) {
return lastResult as R;
}


lastInput = input;
lastResult = combiner(input);
hasCache = true;


return lastResult as R;
}


return ResettableSelector._(select, reset);
}