firstWhere method Null safety

E firstWhere(
  1. bool test(
    1. E element
    ),
  2. {E orElse(
      )?}
    )

    Returns the first element that satisfies the given predicate test.

    Iterates through elements and returns the first to satisfy test.

    Example:

    final numbers = <int>[1, 2, 3, 5, 6, 7];
var result = numbers.firstWhere((element) => element < 5); // 1
result = numbers.firstWhere((element) => element > 5); // 6
result =
    numbers.firstWhere((element) => element > 10, orElse: () => -1); // -1

    If no element satisfies test, the result of invoking the orElse function is returned. If orElse is omitted, it defaults to throwing a StateError.

    Implementation

    E firstWhere(bool test(E element), {E orElse()?}) {
  for (E element in this) {
    if (test(element)) return element;
  }
  if (orElse != null) return orElse();
  throw IterableElementError.noElement();
}