firstWhere method

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

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. Stops iterating on the first matching element.

Implementation

E firstWhere(bool test(E element), {E Function()? orElse}) {
  int length = this.length;
  for (int i = 0; i < length; i++) {
    E element = elementAt(i);
    if (test(element)) return element;
    if (length != this.length) {
      throw ConcurrentModificationError(this);
    }
  }
  if (orElse != null) return orElse();
  throw IterableElementError.noElement();
}