fold<B> method

B fold<B>(
  1. B onNone(
      ),
    1. B onSome(
      1. T t
      )
    )

    Execute onSome when value is Some, otherwise execute onNone.

    [🍌].fold(() => 🍎, (🍌) => 🍌 * 2) -> 🍌🍌
[_].fold(() => 🍎, (🍌) => 🍌 * 2) -> 🍎

    Same as match.

    Implementation

    B fold<B>(B Function() onNone, B Function(T t) onSome) =>
    match(onNone, onSome);