minBy<T extends Comparable<Object>> method Null safety

E? minBy<T extends Comparable<Object>>(
  1. T selector(
    1. int index,
    2. E
    )
)

Returns the first element yielding the smallest value of the given function or null if there are no elements.

For example:

[-3, 2].minBy((_, x) => x * x) // => 2

Implementation

E? minBy<T extends Comparable<Object>>(T Function(int index, E) selector) {
  E? minElem;
  T? minValue;

  forEachIndexed((i, e) {
    final v = selector(i, e);
    if (minValue == null || v.compareTo(minValue!) < 0) {
      minValue = v;
      minElem = e;
    }
  });

  return minElem;
}